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I'm not even arguing that thermal paste is not being applied "correctly" at the factories. I'm arguing that I do not for a second believe it makes a tangible difference to the majority of these systems

Then you better get your believer fixed. If proper thermal paste application can make a big difference on a PC, you better believe the same holds true for Macs.
 
I've not read of a single 2012 iMac needing thermal paste because of throttling. I've never seen a 2012 iMac throttle at ANY point. I'm not even arguing that thermal paste is not being applied "correctly" at the factories. I'm arguing that I do not for a second believe it makes a tangible difference to the majority of these systems, and I'd nigh-guarantee it's nothing to do with the M295X's temperatures under load. Those AMD cards run hot. It's just the way it is.

However, as mentioned earlier, I'd be happy to believe any of these things if some (read: ANY) evidence can be shown that the 2012/2013 iMacs have had improper thermal paste applied. I can just easily cite my own empirical evidence, along with years of forum-going of my own to suggest that there are no widespread (pun intended) thermal-paste issues on the current-design iMacs (2012, 2013, 2014).

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I have a 5K iMac. Do you? No? Then please get one, do a teardown, and make your point. Otherwise, this conversation is over. ;)

Your own empircal evidence of what exactly? Posting on a board and not thinking an engineer who has something valid to input with his line of work. We will see just who is proved right after a couple of years and I will remind you :D

I have no need for a 5k - my old defunct 3,1 soon to be replaced with a flashed 5,1 Mac Pro 6 core with its desktop GTX 680 card will give that option GPU a good kicking playing games, though that is my sons domain. I use my Mac Pro for cuda, CS6, and transcoding and it doesn't throttle one single bit.

I could go on but it feels like I'm the straight Man in a Python sketch too much already discussing technical issues and thermodynamics with you!
 
Your own empircal evidence of what exactly? Posting on a board and not thinking an engineer who has something valid to input with his line of work. We will see just who is proved right after a couple of years and I will remind you :D

I have no need for a 5k - my old defunct 3,1 soon to be replaced with a flashed 5,1 Mac Pro 6 core with its desktop GTX 680 card will give that option GPU a good kicking playing games, though that is my sons domain. I use my Mac Pro for cuda, CS6, and transcoding and it doesn't throttle one single bit.

I could go on but it feels like I'm the straight Man in a Python sketch too much already discussing technical issues and thermodynamics with you!

You're just a person on a message-board, making claims you can't substantiate. That is all. You can't blame me for asking for proof that there's an issue on the current-gen iMac, right? For example, you're the first person I've ever heard of claiming their 2012 iMac actually THROTTLED, for example. I overclocked the snot out of SEVERAL 2012 iMac GPUs and not a single one throttled. At any point.


Then you better get your believer fixed. If proper thermal paste application can make a big difference on a PC, you better believe the same holds true for Macs.

OK, once more - with feeling: I've built and fixed computers for over 20 years. I have a tub full of Arctic Silver 5. I recognize the virtues of proper application.

But again, I've never seen a thermal problem with the 2012/2013 iMacs, and I've not read of anyone having such an issue on either the Macrumors boards or the Apple boards. I'd love to see an example of a 2012 iMac actually throttling the GPU, for example, as was claimed above.

So, it stands to pretty good reason there likely isn't a problem in the 2014 5K iMac in this regard. If you've read about the AMD cards of late, they just run very, very hot. Much, MUCH hotter than the Nvidia cards of yesteryear. Therefore, it again stands to reason that's what 5K owners are experiencing: A much higher TDP GPU in the same chassis. There's your heat.

Now, is it an issue in the longterm? I cannot say. Is it running significantly hotter than the last two iMacs just because of thermal paste misapplication? I'm going to guess no. It's just a much, MUCH hotter GPU. The difference is really staggering.

Will 5K iMacs start failing because of the additional heat? Again, I cannot say. But to go around claiming these iMacs are throttling because of thermal paste issues is just pure conjecture, pure guesswork, and until proven - simply not true.

And I'm done here.
 
Everyone posting does know that these GPU's are designed to run hot, right? The fact that they hit 100C is not necessarily a problem.

Could the iMac have better cooling? Sure. But you can't say it's definitely a problem the R9 hits temperatures it has been designed for. If you're still thinking that anything over 80C is disastrous you have to realise the tech has moved on, about time you did too.

From an Anandtech article dated October 2013, we are even further ahead now:-

Meanwhile from a longevity perspective, while the underlying silicon hasn’t necessarily changed AMD’s understanding of ASIC longevity on TSMC’s 28nm process has. Nearly two years of experience in shipping 28nm GPUs means that AMD has hard evidence for how long a GPU can last at various temperatures, and the maturation of the 28nm process in turn has extended that longevity by improving both the quality and consistency of the GPUs that come out of it. Ultimately there is always going to be a longevity cost to increasing temperatures – and only AMD knows what that cost is – but as the entity ultimately responsible for warrantying their GPUs, at this point AMD is telling us that Hawaii will meet all of their longevity requirements even with the higher operating temperatures.

[source:- http://www.anandtech.com/show/7457/the-radeon-r9-290x-review/5]

Read that page, it's very enlightening.
 
You're just a person on a message-board, making claims you can't substantiate. That is all. You can't blame me for asking for proof that there's an issue on the current-gen iMac, right? For example, you're the first person I've ever heard of claiming their 2012 iMac actually THROTTLED, for example. I overclocked the snot out of SEVERAL 2012 iMac GPUs and not a single one throttled. At any point.

A person who fixes and maintains these for my living who spends some of his free time advising others for free. I have seen these 2012 models throttle - those in video who batter them with cuda and renders for hours on end and hard core gamers too. Seen iMacs have multiple logic boards trying to do a Mac Pro's job and sound like hovercraft when the massively over applied shin-etsu paste dries to a fine light grey dust - with my own eyes. Run hugely cooler and quieter after I've done my work too.

As I mostly have to pick up the pieces post AppleCare or after a year for those crazy enough to know I have no chance of making a comparison until someone in London is brave or mad enough to send me a pm - I will be delighted to share the results.

Getting hot isn't just about the chip or who makes it it's the die area sizes which bind to the heatsink and the watts it consumes. Its just thermodynamics, thermal paste is meant to fill in the gaps between the die and plate and the smoother the surfaces they are you need less paste, about 80% less than Apple apply which gets pushed onto the pcb part of the GPU where it shouldn't go heating that part up - like on the MBP 2011 which is why a lot of their GPU's fail.

And artic silver comes in a syringe not a tub - gelid GC extreme does though and is about the best there is bar the very expensive silver stuff which is a nightmare to apply just right.

Enjoy your 5k and when it gets too hot have a think about doing the thermal paste yourself and minimising that throttling you might end up getting. 20 years of experience has to be put to good use, just don't leave the heat gun in one place for too long!
 
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And artic silver comes in a syringe not a tub - gelid GC extreme does though and is about the best there is bar the very expensive silver stuff which is a nightmare to apply just right.


I suppose I wasn't very clear: Yes, I know that Arctic Silver itself comes in a syringe. :) I have a tub full of it (as in: a tub full of thermal paste and other computer-fixing-related objects). You wouldn't believe how much I've had to use it over the years. Surprised we haven't seen Arctic Silver 6, really, but AS5 is about as good as it gets. Not used GC extreme but I've heard good things.

Anyway, back on topic:

I think the M295X is going to throttle no matter how much thermal paste you put on there, but I'd LOVE to be proven wrong, of course. Until then, I have no intention of ripping apart my iMac. I have numerous adhesive-strip kits to put back the 2012/2013/2014 screens on, so that's not a concern.

And I love my 5K iMac. There's no time like the present, and while it does run hotter (yet to be determined to be an issue), that screen is just the greatest thing since bagels and cream cheese.
 
OK, once more - with feeling: I've built and fixed computers for over 20 years. I have a tub full of Arctic Silver 5. I recognize the virtues of proper application.

The thing is that these issues are common to what happens with improper thermal paste application. And seeing that not everyone is experiencing the issue very well points to improper TP application. I'll concede that this has yet to be proven, but from the variance of people having the issue, it sure does point to TP as the problem. One guy who had the issue returned his for another without issue. This sure does make for strong reasoning.

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And I love my 5K iMac. There's no time like the present, and while it does run hotter (yet to be determined to be an issue), that screen is just the greatest thing since bagels and cream cheese.

Agreed. And all those pixels are sure to push a GPU.
 
i7, 295x, 24GB, 1TB Fusion
Bootcamp 8.1 on USB3 SSD

Farcry 4
1440p, High settings and even Very High, runs like butter.
Only when driving fast I can see little stuttering, might be even driver related since changing settings doesn't seem to fix it.

COD:AW
1440p, High -> runs like butter (finished campaign with 0 issues)

I am severely impressed by the graphics performance of the riMac, I certainly did not expect such results.

Yes it runs hot, but it was designed to.
I've played for 2-3 hours at a time and never seen frame rate drop over time.

http://www.anandtech.com/show/7457/the-radeon-r9-290x-review/5

"What this means for 290X in turn is that one of the biggest reasons for keeping temperatures below 95C has been brought under control. AMD no longer needs to keep temperatures below 95C in order to avoid losing significant amounts of performance to leakage. From a performance perspective it has become “safe” to operate at 95C."

If it throttles, ***** it, because I sure as hell did not notice it while gaming for hours.

P.S. If you are still deciding 2013 or riMac, stop it and do your self and your eyes a favor and get the riMac. The display is just ****** amazing. (that's a period at the end)
 
thats good! mine reaches 102c just watching youtube

Without having too many technical reasons for this (not everybody is a design or component engineer), I just don't feel comfortable having a component inside of my iMac which runs at 105° C...

Many People wouldn't even know and therefore would not mind, but now that I know, it really makes me step away from this without a doubt really nice-screened machine...
 
i7, 295x, 24GB, 1TB Fusion
Bootcamp 8.1 on USB3 SSD

How did you get Win 8.1 running on external USB3 SSD?

I tried Winclone, but I could not boot from the external drive. I mean I could boot, but I got after a time I got a message "windows can't start - must be repaired"

I already tried all the troubleshooting tips from winclone :-(
 
The one upside is that it helps us 2013 owners with our hold-out for 1-2 more generations till the GPU catches up in terms of power efficient matched to the demands made of it.

My wallet thanks me for finding this thread. Mind you, I don't doubt the retina 2014 owners are enjoying the awesome display.
 
How did you get Win 8.1 running on external USB3 SSD?

I tried Winclone, but I could not boot from the external drive. I mean I could boot, but I got after a time I got a message "windows can't start - must be repaired"

I already tried all the troubleshooting tips from winclone :-(

Best guide I found so far:

http://bleeptobleep.blogspot.de/2013/02/mac-install-windows-7-or-8-on-external.html

Might be a bit complicated and you need a Windows machine (or virtual machine), but it does the job.
 
I suppose I wasn't very clear: Yes, I know that Arctic Silver itself comes in a syringe. :) I have a tub full of it (as in: a tub full of thermal paste and other computer-fixing-related objects). You wouldn't believe how much I've had to use it over the years. Surprised we haven't seen Arctic Silver 6, really, but AS5 is about as good as it gets. Not used GC extreme but I've heard good things.

Anyway, back on topic:

I think the M295X is going to throttle no matter how much thermal paste you put on there, but I'd LOVE to be proven wrong, of course. Until then, I have no intention of ripping apart my iMac. I have numerous adhesive-strip kits to put back the 2012/2013/2014 screens on, so that's not a concern.

And I love my 5K iMac. There's no time like the present, and while it does run hotter (yet to be determined to be an issue), that screen is just the greatest thing since bagels and cream cheese.

I know you and many others love AS5, as did I back in the day. I discovered through my own applications that it is not as good as the Ceramique 2. It was consistently a few degrees warmer on just about all applications (CPU, GPU, high contact pressure, low contact pressure) and is highly capacitive (caused some instabilities with some of my home-made electronics).

I should point out that it has been superseded in performance by the Ceramique 2/MX-2/MX-4 and is selling today mostly because of reputation. It is sold at a premium price, I can just imagine the profit.

I'll show you some late/earlier reviews that support my point (and there are plenty more, just that these are my favorites):

http://www.tomshardware.com/charts/thermal-compound-charts/benchmarks,155.html

http://skinneelabs.com/arctic-silver-5-and-ceramique-review/4/

I know old preferences diehard, but I gave away my AS5 and use only Ceramique 2 now. This is mainly because quality thermal compounds are expensive and I just happen to stumble on Ceramique 2 in a large 25g syringe at clearance prices. MX-2 and 4 are even better, but I haven't stocked up on them at cheap cheap prices yet.
 
I know you and many others love AS5, as did I back in the day. I discovered through my own applications that it is not as good as the Ceramique 2. It was consistently a few degrees warmer on just about all applications (CPU, GPU, high contact pressure, low contact pressure) and is highly capacitive (caused some instabilities with some of my home-made electronics).

I should point out that it has been superseded in performance by the Ceramique 2/MX-2/MX-4 and is selling today mostly because of reputation. It is sold at a premium price, I can just imagine the profit.

I'll show you some late/earlier reviews that support my point (and there are plenty more, just that these are my favorites):

http://www.tomshardware.com/charts/thermal-compound-charts/benchmarks,155.html

http://skinneelabs.com/arctic-silver-5-and-ceramique-review/4/

I know old preferences diehard, but I gave away my AS5 and use only Ceramique 2 now. This is mainly because quality thermal compounds are expensive and I just happen to stumble on Ceramique 2 in a large 25g syringe at clearance prices. MX-2 and 4 are even better, but I haven't stocked up on them at cheap cheap prices yet.

Good info, thanks. I don't really have any old habits (*lies, all lies!*), and it's interesting to see how AS5 has been left behind.

I came across this on iFixit, thought those discussing TP replacement might find it a worthwhile read, it's in the Comment > Guide at the bottom of the page.

https://www.ifixit.com/Guide/iMac+Intel+27-Inch+EMC+2639+CPU+Replacement/19630

Also good information. I've yet to have to tinker around with re-applying thermal paste/tape inside the current-chassis iMacs, but it's interesting to note that the recommendations are for tape, here.

It'd be fun to have someone with more time on their hands than me - do some CPU/GPU temperature testing with the 2012-2014 iMacs to see just how much of a difference compound/tape would make to the internal temps.
 
Returned base model 5K Retina

I have a 2012 i7 with 32GB RAM and 2GB Nvidia GPU. It has always worked great. With the iMac 5K Retina i7 and 4GB GPU being backordered for a month (if you complete the shopping cart on the Apple website, right before you confirm, it gives an actual date it will ship, and it's currently longer than 2-3 weeks) I decided..maybe the new base i5 unit will be better than my 2012 i7 unit. So I purchased the base model at my local Apple store.

Yes the screen looks great. But the first thing I noticed was the fan. I was not doing anything..just setting up and I could hear the fan. My older unit is very quite and so is my office..so I was surprised to hear the new iMac have an audible fan when it was essentially doing nothing.

I have good 30mbps broadband so I did some of my traditional web browsing torture tests in Safari.

- The Verge - such a data heavy page to even load..but I did notice something odd. When I would scroll, pictures would be blank then pop in after a second of two. Has anyone seen this? I am guessing that the site is triggering a retina screen and loading in higher res pics. This is just the main page, the large thumbnails. Is this happening for anyone?

- Pinterest - Sign in to Pinterest, do a search, then go into Safari full screen (green button) and do some scrolling. On the iMac 5K it was pretty choppy. Is it smoother with the i7 and 4GB GPU does anyone know?

I did some basic testing and running apps, I did not load any games or anything, just wanted to test basic performance. I found performance a little choppy in places, just web browsing, opening windows, etc. My 2012 i7 is so smooth and the fan so quiet. I am guessing the retina screen and maybe the GPU is holding things back a bit. Or maybe it was just the 8GB of RAM. I would have eventually bumped it up to 32GB.

I ended up boxing it up and retuning it. Not sure what my next move will be. Thinking about the full i7, 4GB GPU, 32GB RAM..but I wonder if they results will be similar. I assume the fan noise will be about the same. I may end waiting until later in 2015 for the next version of the iMac 5K retina...hopefully they can work out some of the kinks. Or maybe I got a bum unit?

All in all I was a bit disappointed. When I upgrade my iMac every couple of years its usually dramatically smoother and faster. I felt the iMac 5k retina was sweating a bit with normal operations, I assume because of the super high res display. While the display was great, it was not great enough that I wanted to put up with the other issues I saw.

My one question..has anyone gotten the i5 base model and then returned it to get the i7 high end model? And what were the results?
 
I have a 2012 i7 with 32GB RAM and 2GB Nvidia GPU. It has always worked great. With the iMac 5K Retina i7 and 4GB GPU being backordered for a month (if you complete the shopping cart on the Apple website, right before you confirm, it gives an actual date it will ship, and it's currently longer than 2-3 weeks) I decided..maybe the new base i5 unit will be better than my 2012 i7 unit. So I purchased the base model at my local Apple store.

Yes the screen looks great. But the first thing I noticed was the fan. I was not doing anything..just setting up and I could hear the fan. My older unit is very quite and so is my office..so I was surprised to hear the new iMac have an audible fan when it was essentially doing nothing.

I have good 30mbps broadband so I did some of my traditional web browsing torture tests in Safari.

- The Verge - such a data heavy page to even load..but I did notice something odd. When I would scroll, pictures would be blank then pop in after a second of two. Has anyone seen this? I am guessing that the site is triggering a retina screen and loading in higher res pics. This is just the main page, the large thumbnails. Is this happening for anyone?

- Pinterest - Sign in to Pinterest, do a search, then go into Safari full screen (green button) and do some scrolling. On the iMac 5K it was pretty choppy. Is it smoother with the i7 and 4GB GPU does anyone know?

I did some basic testing and running apps, I did not load any games or anything, just wanted to test basic performance. I found performance a little choppy in places, just web browsing, opening windows, etc. My 2012 i7 is so smooth and the fan so quiet. I am guessing the retina screen and maybe the GPU is holding things back a bit. Or maybe it was just the 8GB of RAM. I would have eventually bumped it up to 32GB.

I ended up boxing it up and retuning it. Not sure what my next move will be. Thinking about the full i7, 4GB GPU, 32GB RAM..but I wonder if they results will be similar. I assume the fan noise will be about the same. I may end waiting until later in 2015 for the next version of the iMac 5K retina...hopefully they can work out some of the kinks. Or maybe I got a bum unit?

All in all I was a bit disappointed. When I upgrade my iMac every couple of years its usually dramatically smoother and faster. I felt the iMac 5k retina was sweating a bit with normal operations, I assume because of the super high res display. While the display was great, it was not great enough that I wanted to put up with the other issues I saw.

My one question..has anyone gotten the i5 base model and then returned it to get the i7 high end model? And what were the results?

I'm really interested as to why you felt the 5K iMac had a noisier fan than the 2012. I have (now - had) both systems next to each other. Maxed out 2012 iMac 27" and my maxed out 5K iMac, and they both sound absolutely identical. If I had to bet (and I'm not a betting man), I'd wager the fan in each system is exactly the same. The quality of the sound is identical. It's possible the 5K iMac you had was not quite "right," (i.e. fan bearing slightly off etc). In any case, when idling - 1200rpm, the fan noise should be identical.

I can see The Verge's thumbnails pop in a second after scrolling through. I suspect it's something to do with the way Safari is doing its rendering. Chrome (the latest build 39 with 64bit support) does it VERY differently, and scrolling up and down The Verge's homepage in Chrome is a laggy, ghastly affair. With Safari it's buttery smooth.

I can't speak for going from a 5K base model to the high-end, but I'm really pleased with my high-end model. Really, really pleased so far (barring some WiFi issues in Yosemite).
 
Yes the screen looks great. But the first thing I noticed was the fan. I was not doing anything..just setting up and I could hear the fan. My older unit is very quite and so is my office..so I was surprised to hear the new iMac have an audible fan when it was essentially doing nothing.

That doesn't sound normal at all. The base model should be quiet unless it's pushed really hard. It's the upgraded one that heats up very quickly.

Did you check if there was any process hogging up the CPU? SMC reset? What speed was your fan running at?

If it's not a software issue then it might have been badly applied thermal paste or a faulty fan. It shouldn't sound more than the 2012 iMac.
 
That doesn't sound normal at all. The base model should be quiet unless it's pushed really hard. It's the upgraded one that heats up very quickly.

Did you check if there was any process hogging up the CPU? SMC reset? What speed was your fan running at?

If it's not a software issue then it might have been badly applied thermal paste or a faulty fan. It shouldn't sound more than the 2012 iMac.

The base I have is very quiet, I've yet to hear the fans spin up above normal idle even when watching Netflix, Hulu streams, etc. I have not pushed it CC filters, gaming, etc.

I have managed to fill ram up ( 32GB ) with idea projects, MS Word, MS Excel, Sublime text, Cyberduck, CC Photoshop, many safari and chrome windows and watching netflix in safari on external 1080 monitor all open at the same time and nothing above idle fan noise, which I can barely hear in a quiet room.

My unit's observation.
 
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