2019 iMac - i5 vs i9? Cooling and Throttling?

[Bboble]

Restricting a processor’s power input? Intel’s specs state 95 W. And the same information that Apple provides - 3.6 GHz.

https://www.intel.com/content/www/us/en/products/processors/core/i9-processors/i9-9900k.html

So it comes already thermal throttled? No people just need to stop using that term for cases like this one. We have not seen any evidence that it goes below 3.6 GHz when hot which is what thermal throttling is. Apparently is is very difficult to even get the fans going!

Watts=Power
Power=Heat
Heat=Thermal. Yes, it's pleasing to see the i9 can run a few hundred megahertz above base frequency at 85 watts as has been shown. This is great, but, far short of what the chip can—and was designed—to do.

95 watts is used as a "design" spec to equate a processor to a cooling solution that can dissipate said wattage at base frequencies. However, while both the 9600k and 9900k are each rated at 95 watts, the 9900k has been shown to pull about twice the wattage unrestricted, and running per Intel rated specs.

In the case of the i9 in the iMac, A LOT of potential performance is left on the table. Whereas, much less performance is left on the table with respect to the i5. Performance is left on the table due to thermal throttling.

 

[Ethosik]

Watts=Power
Power=Heat
Heat=Thermal. Yes, it's pleasing to see the i9 can run a few hundred megahertz above base frequency at 85 watts as has been shown. This is great, but, far short of what the chip can—and was designed—to do.

95 watts is used as a "design" spec to equate a processor to a cooling solution that can dissipate said wattage at base frequencies. However, while both the 9600k and 9900k are each rated at 95 watts, the 9900k has been shown to pull about twice the wattage unrestricted, and running per Intel rated specs.

In the case of the i9 in the iMac, A LOT of potential performance is left on the table. Whereas, much less performance is left on the table with respect to the i5. Performance is left on the table due to thermal throttling.

It has a TDP of 95 W. How is it "designed" to operate at a sustained 4.7Ghz at 95 W TDP?

I am not trying to be difficult here, I guess I am missing something obvious that the Intel spec sheet has it already thermal throttling by default? It is designed with the minimum clock speed of 3.6Ghz. Turbo boost to 5 Ghz is just a bonus. It is not designed for sustained 4.7Ghz otherwise they would list it as the minimum clock speed.

 

[Bboble]

It has a TDP of 95 W. How is it "designed" to operate at a sustained 4.7Ghz at 95 W TDP?

I am not trying to be difficult here, I guess I am missing something obvious that the Intel spec sheet has it already thermal throttling by default? It is designed with the minimum clock speed of 3.6Ghz. Turbo boost to 5 Ghz is just a bonus. It is not designed for sustained 4.7Ghz otherwise they would list it as the minimum clock speed.

Perhaps I am the one being difficult, but on count of Apple, not yourself. You are correct, in that the processor is guaranteed to hit 3.6GHz all core with no more than 95 watts. That defines the TDP. That being said, Intel does not restrict the processor to 95 watts, as this is a “design” guideline. Apple, ultimately is the one to implement the chip in their systems as they see fit.

My dilemma, is that Intel designed the 9900k to run at a sustained 4.7GHz on all cores, whereas the 9600k i5 was designed to sustain 4.3GHz. The fact that the i5 appears to sustain within 100MHz of design at load, and the i9 is throttled nearly 1000MHz at load is hugely problematic to me, and should be to all their customers.

While anything above the base clock may be considered a bonus, it’s a bonus that’s advertised by Apple, and not delivered. Apple has the ability to limit the boost as they see fit, and advertise accordingly, but they omit this kind gesture.

I find it most odd that Apple skipped the 9700k i7. While it is not hyper-threaded, I wouldn’t be surprised if it performed identical, or better in some use cases than the i9. For this, Apple is just using the marketing of the i9, but, you’re loosing a lot of performance potential. Most troubling, is it’s potential that could be better realized with the cooler of the iMac Pro. This is an embarrassment.

 

[propower]

Yes the i5 appears faster at full load by 400 or so MHz. But the i9 can do 16 threads - while the i5 does 6 at that temp/freq. In many cases the i9 is clearly "better- faster at the task" due to concurrent threads than the i5 despite the freq difference "apparently" favoring the i5. Though for others tasks - the i5s faster clock is the real advantage. Each has its strengths (IMO ) That the cooling ib the current iMac limits the overall dissipation to 95W or so is just reality. That they didn't redesign and use the iMac Pro cooling is interesting.

 

[Ethosik]

Perhaps I am the one being difficult, but on count of Apple, not yourself. You are correct, in that the processor is guaranteed to hit 3.6GHz all core with no more than 95 watts. That defines the TDP. That being said, Intel does not restrict the processor to 95 watts, as this is a “design” guideline. Apple, ultimately is the one to implement the chip in their systems as they see fit.

My dilemma, is that Intel designed the 9900k to run at a sustained 4.7GHz on all cores, whereas the 9600k i5 was designed to sustain 4.3GHz. The fact that the i5 appears to sustain within 100MHz of design at load, and the i9 is throttled nearly 1000MHz at load is hugely problematic to me, and should be to all their customers.

While anything above the base clock may be considered a bonus, it’s a bonus that’s advertised by Apple, and not delivered. Apple has the ability to limit the boost as they see fit, and advertise accordingly, but they omit this kind gesture.

I find it most odd that Apple skipped the 9700k i7. While it is not hyper-threaded, I wouldn’t be surprised if it performed identical, or better in some use cases than the i9. For this, Apple is just using the marketing of the i9, but, you’re loosing a lot of performance potential. Most troubling, is it’s potential that could be better realized with the cooler of the iMac Pro. This is an embarrassment.

If it was Intel's design, why wouldn't they require more than 95 TDP? If their design is to never go that low and to always achieve a sustained 4.7 Ghz no matter what, why even list the 95 TDP in the design specs in the first place?

This isn't like Apple making it only have 3.0 Ghz or less. It is perfectly within the specs of Intel's sheet online. I do not see in their spec sheet that the i9-9900k is designed to run at 4.7 Ghz.

Have you seen any of the performance videos? The fact that the processor is operating at 3.8 Ghz in nearly all tests during sustained load means it IS achieving what is advertised with the turbo clock as 3.8 > 3.6. And in some tests it did operate at 4+ Ghz too. I do not understand how this is false advertising or they do not deliver what they state.

 

[Rockadile]

Perhaps I am the one being difficult, but on count of Apple, not yourself. You are correct, in that the processor is guaranteed to hit 3.6GHz all core with no more than 95 watts. That defines the TDP. That being said, Intel does not restrict the processor to 95 watts, as this is a “design” guideline. Apple, ultimately is the one to implement the chip in their systems as they see fit.

My dilemma, is that Intel designed the 9900k to run at a sustained 4.7GHz on all cores, whereas the 9600k i5 was designed to sustain 4.3GHz. The fact that the i5 appears to sustain within 100MHz of design at load, and the i9 is throttled nearly 1000MHz at load is hugely problematic to me, and should be to all their customers.

While anything above the base clock may be considered a bonus, it’s a bonus that’s advertised by Apple, and not delivered. Apple has the ability to limit the boost as they see fit, and advertise accordingly, but they omit this kind gesture.

I find it most odd that Apple skipped the 9700k i7. While it is not hyper-threaded, I wouldn’t be surprised if it performed identical, or better in some use cases than the i9. For this, Apple is just using the marketing of the i9, but, you’re loosing a lot of performance potential. Most troubling, is it’s potential that could be better realized with the cooler of the iMac Pro. This is an embarrassment.

Macs has always leaned to form over function. Wasting performance potential is not a deal breaker for iMac target group. This was clear when they thinned the back even more for the 2012 refresh. The ones that would care is the abandoned and clinging cMP users.

A 95W limited 9900K can still do 5Ghz on a single core so Apple is within the fine print, like it or not.

They probably skipped the 9700K to inflate the difference. Same BS they do with iPhone storage space now.

 

[joema2]

...Intel designed the 9900k to run at a sustained 4.7GHz on all cores...While anything above the base clock may be considered a bonus, it’s a bonus that’s advertised by Apple, and not delivered....

Apple is not doing anything different from other leading manufacturers of business-class air-cooled i9-9900k PCs. I just heard directly from Puget Systems. They confirmed they do NOT enable unrestricted thermal mode on their air-cooled i9-9900k systems. Likewise I haven't found any other PC manufacturer who does this for air-cooled business-class systems.

Some will ship and support a liquid-cooled i9-9900k gaming system with unrestricted thermal mode enabled -- just like they will ship and support a heavily-overclocked liquid-cooled system. But this has nothing to do with Apple iMacs and general-purpose air-cooled business-class manufactured PCs.

 

[Bboble]

It seems Apple may have intentionally poisoned the water with the thermal throttling MBP last year. It seems everyone has become desensitized to throttling. Yes, Mac throttling is not a new phenomenon. They're always pushing the thermal envelop. In the case of the i9 iMac, they're leaving way more performance on the table than is reasonable. When other air-cooled systems are getting close to a thousand more points (~20% higher) in Cinebench R20, this is a problem! It is well-published that the 9900k will do 4.7GHz full tilt on all 8 cores. To leave nearly a GHz on the table is unacceptable. The i5 iMac, on the other hand, is well within reason, and, has been shown to turbo higher than the i9, despite what Apple advertises.

Yes, Intel pushed out one hot processor with the 9900k, but, they did this so as to not let AMD take the lead while they get their 10nm process figured out. That is Intel's problem, yes, but, Apple made the decision to include the 9900k, and, they did a piss-poor implementation. Most notably, because a more suitable cooler had already been engineered for the iMac Pro. Not to mention, a comparably equipped iMac to the Pro is $4250. When I've often seen the iMac Pro for $4000, Apple is fragmenting their already fragmented product line. When I can get a server grade processor, ECC memory, more PCI-e lanes, more I/O, stereo speakers, better microphones, a reasonable resolution of a webcam for 2019, and maybe more(?) why would I pay more for less!? The regular iMac should be better singlethreaded, but, multithreaded, the machines are nearly equal from what I can see.

I've been a mac fanboy for decades, but I've been on the fence about them for awhile. This is just another straw in their disingenuous journey.

Regarding Puget systems, from what I can discern, I see their 9900k system falls leauges above the iMac, and, inline with stock 9900k systems unrestrained. Please correct me if I am wrong here.

 

[Rockadile]

It seems Apple may have intentionally poisoned the water with the thermal throttling MBP last year. It seems everyone has become desensitized to throttling. Yes, Mac throttling is not a new phenomenon. They're always pushing the thermal envelop. In the case of the i9 iMac, they're leaving way more performance on the table than is reasonable. When other air-cooled systems are getting close to a thousand more points (~20% higher) in Cinebench R20, this is a problem! It is well-published that the 9900k will do 4.7GHz full tilt on all 8 cores. To leave nearly a GHz on the table is unacceptable. The i5 iMac, on the other hand, is well within reason, and, has been shown to turbo higher than the i9, despite what Apple advertises.

Yes, Intel pushed out one hot processor with the 9900k, but, they did this so as to not let AMD take the lead while they get their 10nm process figured out. That is Intel's problem, yes, but, Apple made the decision to include the 9900k, and, they did a piss-poor implementation. Most notably, because a more suitable cooler had already been engineered for the iMac Pro. Not to mention, a comparably equipped iMac to the Pro is $4250. When I've often seen the iMac Pro for $4000, Apple is fragmenting their already fragmented product line. When I can get a server grade processor, ECC memory, more PCI-e lanes, more I/O, stereo speakers, better microphones, a reasonable resolution of a webcam for 2019, and maybe more(?) why would I pay more for less!? The regular iMac should be better singlethreaded, but, multithreaded, the machines are nearly equal from what I can see.

I've been a mac fanboy for decades, but I've been on the fence about them for awhile. This is just another straw in their disingenuous journey.

Regarding Puget systems, from what I can discern, I see their 9900k system falls leauges above the iMac, and, inline with stock 9900k systems unrestrained. Please correct me if I am wrong here.

Where are these well published articles of 9900K doing all-core 4.7GHz in a AIO?

The 9900K's performance (that's not constrained in a AIO) blurs the line between top-end consumer and entry HEDT. Pretty much cannibalized Intel's low end HEDT chips.

Apple decided to rest on their laurel and milk the profit from using the same iMac chassis. They just barely managed the fine print (i9 5.0Ghz single core @ 95W limited) and they may not even bother to change the innards if future 10nm chips produce less heat. The 9900K was a knee jerk reaction to AMD after all.

 

[Colonel Blimp]

The i5 iMac, on the other hand, is well within reason, and, has been shown to turbo higher than the i9, despite what Apple advertises.

You’ve made that claim several times, but I’ve yet to see any evidence for it. (Perhaps I simply missed it.) Please show us the results of a test where, in a 2019 iMac, a six-core i5 sustains a higher turbo boost clock rate with all six cores maxed out than an i9 with six cores maxed out. I don’t see how comparing six-core turbo boost frequencies to eight-core turbo boost frequencies is relevant.

Both Cinebench R20, which tests all cores under sustained load, and Geekbench 4 show the i9-9900 scoring 55% higher than the i5-9600 in the 2019 iMac. Clearly the i9 is delivering far more multi-core performance within the iMac’s thermal constraints than the i5. (Even the i9’s single-core Geekbench 4 scores exceed those of the i5, though of course not by nearly as much.) Pardon me if I’m being obtuse, but I just don’t understand your complaint.

Yes, Intel pushed out one hot processor with the 9900k, but, they did this so as to not let AMD take the lead while they get their 10nm process figured out. That is Intel's problem, yes, but, Apple made the decision to include the 9900k, and, they did a piss-poor implementation. Most notably, because a more suitable cooler had already been engineered for the iMac Pro.

The cooling system in the iMac Pro leaves no room for a hard drive. (Before you say, “Apple shouldn’t be shipping iMacs with hard drives,” see my reply to your next point.)

Not to mention, a comparably equipped iMac to the Pro is $4250. When I've often seen the iMac Pro for $4000, Apple is fragmenting their already fragmented product line. When I can get a server grade processor, ECC memory, more PCI-e lanes, more I/O, stereo speakers, better microphones, a reasonable resolution of a webcam for 2019, and maybe more(?) why would I pay more for less!?

That’s only if you pay Apple $600 to upgrade the iMac to 32 GB of RAM. If instead you buy, say, 32 GB of Crucial RAM yourself, you can get a comparably equipped iMac for $3,848 total, which is still less than a refurbished iMac Pro. But you’re right in that right now a refurbished iMac Pro is a better deal if you want only 1TB of internal storage.

(Of course, Apple will eventually sell refurbished 2019 iMacs, and then a refurbished iMac Pro will be even more expensive by comparison.)

However, if you wanted an iMac Pro equipped comparably to the 2019 iMac I just ordered (i.e. one with a minimum of 3 TB internal storage, since Boot Camp must reside on the internal drive), it would cost you $7,399 instead of the $3,458 I paid!

 

[AndreeOnline]

Too much unsupervised "thinking" going on here.

Instead of venting, people critical of the iMac should use their insights to drive personal satisfaction when building their own computer.

The whole concept of using PCpartpicker to list a handful of components and then compare the price of that "computer" (not even built yet—just a parts list) to an iMac, is getting really old. Fast.

Occasionally, I see people who compare Mac to Windows based systems ("PCs") claim "...and then you pay $$$ for the ". They are actually right, but they rarely get it. They say this to mock Apple users, or to somehow insinuate that these less computer savvy sheep pay loads of cash for a logo.

"This bad boy...", they'll say (raising their voice to overpower the fans), slapping their 3 inch thick, plastic "portable" computer that's huffin' and puffin', with a small, horizontally offset trackpad.... *

If the brand (material selection, component selection, design and assembly skill, price, ethics) doesn't mean anything to you—don't buy it.

The iMac is Apple's version of the inevitable compromise that is an 'all-in-one'. You get a coherent, refined computer that is limited on several fronts. This compromise fits many bills, but might not fit yours. If you don't like it, don't buy it.

Even if I'd prefer a CFast card reader in an iMac, there really is zero point in beating that horse. Yes, I too would have liked to have seen the iMac Pro cooling in the new iMac, just as I would have liked HDR OLED screens by now (without any of the drawbacks of course!!). And if an iPad Pro is as fast as a MacBook Pro, why doesn't the iMac come with 6 of those systems built into that huge case? And so on...

While it's important to keep track of actual design problems or faulty hardware/firmware, that isn't the case here.


* = now, if someone comes to think of a computer that is a much better design than an iMac or MacBook Pro—don't waste time telling me about it! Just buy it and be happy already!

 

[Bboble]

This has gotten out of hand.

I don't believe I've ever complained that the iMac i9 is a slouch of a machine. However, it is hardly leveraging the capabilities of the processor. The fact that the majority seem to be okay with Apple's direction, is exactly what permits Apple to continue down that path.

AnandTech is just one of many sources in where you'll find this. At six or eight cores loaded, the 9900k is rated at 4.7GHz. In the sustained tests, I think we've all seen that that the i9 hunts around 3.8–3.9 GHz. Whereas, the i5 is actually sitting at ~4.2 GHz full tilt. Now, these are both "95 watt" chips, and, Apple claims the i9 boosts higher (400MHz higher) than the i5, but it seems the i5 actually boosts ~400MHz higher than the i9. Does anyone have other numbers that the processors are sustaining?

Now, it would be most interesting to see what turning off two cores would do to the i9 (and maybe even hyper-threading). As many have refuted claims that it is throttling, that wouldn't support an increased frequency with less cores. If it was throttling, however, restricting core count would then raise the frequency of the remaining cores as there would then be more thermal headroom. This would help to put the battle to rest. Is someone with an i9 iMac willing to do this?

In the end, if the iMac works for you, and your workflow, great! You will not find a more polished machine elsewhere. Just know that the i5 is performing closer to Intel intended specs, than the i9. If raw megahertz is important in your workflow, know that you'll get more with the i5, than the i9 (despite Apple's claim). If thread count is important, the i9 will do laps around the i5.

 

[Chancha]

At six or eight cores loaded, the 9900k is rated at 4.7GHz. In the sustained tests, I think we've all seen that that the i9 hunts around 3.8–3.9 GHz. Whereas, the i5 is actually sitting at ~4.2 GHz full tilt. Now, these are both "95 watt" chips, and, Apple claims the i9 boosts higher (400MHz higher) than the i5, but it seems the i5 actually boosts ~400MHz higher than the i9. Does anyone have other numbers that the processors are sustaining?

This is the most important info to know, that if the i5 9600k with only 6C6T is sustaining a higher turbo clock across 6 threads, then for some tasks then it is going to outperform the 9900k's at lower lock across 16 threads. Some apps like Adobe CC's probably are not going to utilize threads beyond 6 for certain tasks. And the fact that it costs less to config with the i5, and then it most def will be cooler and makes less fan noise are also important.

At this point I would say the iMac with i9 while restrained, it is way more performant and quiet than the 2017 line up. I have a maxed out 2017 27" myself, it is a lovely machine by most measures, but the noise level it gets into is one really glaring short coming, and it only takes a medium load to kick into full speed. So in the context of Mac(OS) users, this 2019 line up is a pretty decent choice, but in a spec-to-spec perspective the i9 config (+VEGA) is not providing a good cost to performance ratio, due to inherent thermal / power constraints of the chassis design. Apple could have moved down the dual-fan setup in the iMac Pro to the regular iMac but they haven't, probably due to product segregation. But then as a "bonus" we are not getting the troublesome T2 chip. I agree with an above user, 2019 iMac will probably be deemed as one last good model of iMac like the 2015 MBP is, both are reasonably performant while being almost issue-free.

 

[amoergosum]

If raw megahertz is important in your workflow, know that you'll get more with the i5, than the i9 (despite Apple's claim). If thread count is important, the i9 will do laps around the i5.

If you want to do RAW editing in Lightroom/Photoshop and 4K editing in Final Cut Pro, the i9 is the better choice, correct?

 

[Returnoftheimac]

I would recommend the i9 as it is the recommended CPU from Puget Systems for Photoshop ( Although they build PCs so are not directly comparable).


See the attached bench marks.



I hope that helps you inform your choice.

 

[jdmagoo1]

If you want to do RAW editing in Lightroom/Photoshop and 4K editing in Final Cut Pro, the i9 is the better choice, correct?

Correct!

 

[Chancha]

If you want to do RAW editing in Lightroom/Photoshop and 4K editing in Final Cut Pro, the i9 is the better choice, correct?

You need to see a test that literally use Lightroom with the 2 iMacs of the 2 CPU configs to be sure. The unknown factor is how the behaviour of Apple's tuning of the respective cooling logic will affect LR usage. The other tricky part is how LR/PS utilize the 7th thread and beyond which is only available on the i9.

 

[Rockadile]

This has gotten out of hand.

I don't believe I've ever complained that the iMac i9 is a slouch of a machine. However, it is hardly leveraging the capabilities of the processor. The fact that the majority seem to be okay with Apple's direction, is exactly what permits Apple to continue down that path.

AnandTech is just one of many sources in where you'll find this. At six or eight cores loaded, the 9900k is rated at 4.7GHz. In the sustained tests, I think we've all seen that that the i9 hunts around 3.8–3.9 GHz. Whereas, the i5 is actually sitting at ~4.2 GHz full tilt. Now, these are both "95 watt" chips, and, Apple claims the i9 boosts higher (400MHz higher) than the i5, but it seems the i5 actually boosts ~400MHz higher than the i9. Does anyone have other numbers that the processors are sustaining?

Now, it would be most interesting to see what turning off two cores would do to the i9 (and maybe even hyper-threading). As many have refuted claims that it is throttling, that wouldn't support an increased frequency with less cores. If it was throttling, however, restricting core count would then raise the frequency of the remaining cores as there would then be more thermal headroom. This would help to put the battle to rest. Is someone with an i9 iMac willing to do this?

In the end, if the iMac works for you, and your workflow, great! You will not find a more polished machine elsewhere. Just know that the i5 is performing closer to Intel intended specs, than the i9. If raw megahertz is important in your workflow, know that you'll get more with the i5, than the i9 (despite Apple's claim). If thread count is important, the i9 will do laps around the i5.

You're confused. Apple never claimed 9900K will do all-cores @ 4.7GHz, only 5GHz one/two cores.

The 9900K uses 95W when running all-cores @ 3.6GHz. That's the "official" rated value. It will use more watts (125W+) with all-cores @ 4.7GHz. TDP is like the rated MPG value on a vehicle. You'll get more or less MPG on how you drive it. Same with the 9900K, you'll use more or less watts depending on the load you put on it. There's no official MPG value going 200MPH and neither is there a TDP value going all-core 4.7GHz.

Also note that the 9900K chip in the iMac has a watt limit set like a vehicle with a speed limiter, it's only getting 85W on full continuous load.

A 9900K to get speeds like your chart needs way more than 85W.

 

[quagmire]

The watts being limited to 85W instead of 95W under full load is a more justifiable outrage than crying over an unrestricted 9900K able to sustain 4.7 GHz on all cores. But even with the watts restricted 10W lower than the advertised max, it seems to be performing better than anandtech’s test when they restricted it to 95W at least with more cores loaded. The highest I seen the CPU go on 1-2 cores is 4.8 GHz where they saw it hit 5 GHz.

When I get a chance, I will limit Cinebench to 6 threads and see what the i9 runs at to see if a 9600K will beat the 9900K on a task that really take advantage of 6 cores.
[doublepost=1554208891][/doublepost]Update: Ran Cinebench limiting it to 6 threads the i9 ran a consistent 4.5 Ghz with a score of 2749. Someone with a 9600K got 2595 at a speed of 4.2 Ghz. So the 9900K is still faster limited to 6 cores/6 threads than a 9600K going full tilt.

 

[Bboble]

You're confused. Apple never claimed 9900K will do all-cores @ 4.7GHz, only 5GHz one/two cores.

Where did they claim this about core counted boost? I see they advertise 5GHz, but no fine print that it only applies to two cores. Maybe I missed it? And, where do they claim it's 95W restricted? As noted, it's restricted to something more like 85 watts, which is thermal throttling. Regardless, it's thermal throttling to restrict it to any wattage, including 95 watts. Again, TDP is a design parameter, not a hard number. I am well aware of the correlation between wattage input to performance output.

This is not the first time macs have thermal throttled, but, I believe this is the most performance they've ever left on the table. It is very ballsy to put such a beast of a chip in a computer that can not adequately cool, or utilize it to its rated potential.
[doublepost=1554215855][/doublepost]

Ran Cinebench limiting it to 6 threads the i9 ran a consistent 4.5 Ghz with a score of 2749. Someone with a 9600K got 2595 at a speed of 4.2 Ghz. So the 9900K is still faster limited to 6 cores/6 threads than a 9600K going full tilt.

Thank you for running this. The fact that the speed increased by ~6–700MHz highlights just how much this chip is being throttled. I have no doubt in my mind that the i9 iMac has serious horsepower. It's just highly disappointing to see Apple's implementation of the chip.
[doublepost=1554218359][/doublepost]

This is the most important info to know, that if the i5 9600k with only 6C6T is sustaining a higher turbo clock across 6 threads, then for some tasks then it is going to outperform the 9900k's at lower lock across 16 threads. Some apps like Adobe CC's probably are not going to utilize threads beyond 6 for certain tasks. And the fact that it costs less to config with the i5, and then it most def will be cooler and makes less fan noise are also important.

Correct. Whereas it should be as simple as saying the i9 will outperform the i5 in all use cases, this may actually not be the case.

 

[mcnallym]

Where did they claim this about core counted boost? I see they advertise 5GHz, but no fine print that it only applies to two cores. Maybe I missed it? And, where do they claim it's 95W restricted? As noted, it's restricted to something more like 85 watts, which is thermal throttling. Regardless, it's thermal throttling to restrict it to any wattage, including 95 watts. Again, TDP is a design parameter, not a hard number. I am well aware of the correlation between wattage input to performance output.

This is not the first time macs have thermal throttled, but, I believe this is the most performance they've ever left on the table. It is very ballsy to put such a beast of a chip in a computer that can not adequately cool, or utilize it to its rated potential.
[doublepost=1554215855][/doublepost]

Thank you for running this. The fact that the speed increased by ~6–700MHz highlights just how much this chip is being throttled. I have no doubt in my mind that the i9 iMac has serious horsepower. It's just highly disappointing to see Apple's implementation of the chip.
[doublepost=1554218359][/doublepost]

Correct. Whereas it should be as simple as saying the i9 will outperform the i5 in all use cases, this may actually not be the case.

https://www.intel.com/content/www/us/en/products/processors/core/i9-processors/i9-9900k.html

Is the official intel page for the chip

Clearly gives 95w
The explaination of turbo frequency clearly states on 1 core.

They are the specs that the cpu needs to do.

If two less cores running then they aren’t drawing power and putting out heat thus allowing the remaining cores running to run faster.

It is not thermal throttling to simply meet specification from intel. Yes IF was a bigger enclosure and IF had bigger cooling then could run higher speeds for longer, however this is an AIO and has compromises to make.

That is true also of pretty much every sold pre-built unless buying from a boutique seller that specialises in overclocked systems.

Unless seeing iMacs bouncing along at under the specs then not bothered.

If you ( and not specifically you but generic you ) are bothered then no AIO is going to be suitable. In fact probably say that NO Mac period is going to be suitable for you.

 

[hans1972]

Exactly, those expectations have been set when the customer hits add to basket. Apple need to be more open in what’s been sold.

Turbo Boost is not meant to be on all the time, only when required and the thermal envelope allows it.

I have always believed that turbo boost is something that only lasts for a few seconds.

 

[joema2]

.
...IF was a bigger enclosure and IF had bigger cooling then could run higher speeds for longer, however this is an AIO and has compromises to make....That is true also of pretty much every sold pre-built unless buying from a boutique seller that specialises in overclocked systems...

I agree with this. Actually, running the i9-9900k within Intel's default 95W TDP does not appear isolated to AIO systems. As you said -- most every pre-built air-cooled business-class PC from a major manufacturer does not ship with the BIOS configured for unrestricted thermal mode. That means it's not the Mac's slim AIO design -- it's pretty much every air-cooled mainstream i9-9900k PC -- including large towers -- from major manufacturers.

There are definitely some boutique builders who will ship you a liquid-cooled i9-9900k PC configured for unrestricted thermal mode, just like they will ship you one which is overclocked. They will also support it, but you pay for that. Those are not mainstream business-class machines and they don't have air-cooled CPUs.

 

[hans1972]

Perhaps I am the one being difficult, but on count of Apple, not yourself. You are correct, in that the processor is guaranteed to hit 3.6GHz all core with no more than 95 watts. That defines the TDP. That being said, Intel does not restrict the processor to 95 watts, as this is a “design” guideline. Apple, ultimately is the one to implement the chip in their systems as they see fit.

If a CPU is rated for 3.6GHz, it means to me that it should be able to run at 3.6GHz for an extended amount of time (several hours).

Turbo Boost means only the ability to increase the speed for a short amount time (measured in seconds).

If a 3.6GHz CPU with 4.8GHz Turbo boost should be able to run at 4.8GHz all the time, why not just call it a 4.8GHz CPU?

So to me, any reduction of CPU speed which occurs above 3.6GHz is not throttling.

You seem to have another viewpoint.

 

[Ethosik]

If a CPU is rated for 3.6GHz, it means to me that it should be able to run at 3.6GHz for an extended amount of time (several hours).

Turbo Boost means only the ability to increase the speed for a short amount time (measured in seconds).

If a 3.6GHz CPU with 4.8GHz Turbo boost should be able to run at 4.8GHz all the time, why not just call it a 4.8GHz CPU?

So to me, any reduction of CPU speed which occurs above 3.6GHz is not throttling.

You seem to have another viewpoint.

This is what I find very confusing. If Intel “designed” this processor to operate at 4.7 GHz instead of 3.6, why even list/support 95 W TDP? If it’s not within the design spec, why is it on their spec sheet?