AMD Radeon R9 M295X Core Clock Throttling, Heat, and Performance

[andy9l]

This may or may not be of interest to you guys still on the fence about it all. I removed the person's name out of courtesy.

It's the last day for Christmas returns tomorrow.

Best of luck to all, regardless of your decision, and thanks for your help in making my decision. Mega useful thread.

 

[WilliamG]

This may or may not be of interest to you guys still on the fence about it all. I removed the person's name out of courtesy.

It's the last day for Christmas returns tomorrow.

Best of luck to all, regardless of your decision, and thanks for your help in making my decision. Mega useful thread.

Image

That person knows know not what he/she speaks. ALL iMacs with the i7/295 run hot. Period. The end. If they're all defective, then maybe that person has a point. But until then, simply - no.

 

[carlob]

That person knows know not what he/she speaks. ALL iMacs with the i7/295 run hot. Period. The end. If they're all defective, then maybe that person has a point. But until then, simply - no.

Exactly, it's not an issue of a specific faulty imac. All retina imacs with the 295 gpu run hot, every single one, so if they are defective by design (which I don't think) it's gonna be a very big issue for apple. No point to get a replacement, if you can't live with the concern that it will blow better get your money back.

 

[andy9l]

If they're all defective, then maybe that person has a point.

Forgive me if I'm wrong, but I thought that's what this thread was about? A potential design flaw.

From the OP:

Unfortunately, there is no way around it, heat is a tremendous problem with these new iMacs and I fear we have a gimped M295X because of it.

 

[WilliamG]

Forgive me if I'm wrong, but I thought that's what this thread was about? A potential design flaw.

From the OP:

Right, but clearly the Apple rep isn't seeing that..

 

[andy9l]

Right, but clearly the Apple rep isn't seeing that..

Sorry buddy, I don't follow?

I'm not trying to be a nuisance here, I want to keep this thing in front of me just as much as the next guy - I'm just very skeptical.

I need some kind of proof that, out of nowhere, AMD hardware is now suddenly able to withstand consistent 105-110ºC temperatures. So far, all I've found is 100ºC is trouble time, and the two Apple reps I've spoken to have both urged me to get it seen to due to the excessive temperatures. If you find something to the contrary, please, please post it.

 

[WilliamG]

Sorry buddy, I don't follow?

I'm not trying to be a nuisance here, I want to keep this thing in front of me just as much as the next guy - I'm just very skeptical.

I need some kind of proof that, out of nowhere, AMD hardware is now suddenly able to withstand consistent 105-110ºC temperatures. So far, all I've found is 100ºC is trouble time, and the two Apple reps I've spoken to have both urged me to get it seen to due to the excessive temperatures. If you find something to the contrary, please, please post it.

A lot of AMD desktop GPUs can run very, very hot. This isn't a surprise.

I'm just saying that what the rep in that chat is saying is they're essentially all defective. Well, I certainly don't think that's true. In fact, if just the GPU and CPU are running that hot, it does NOT necessarily mean there's an issue. My wife's 2011 MacBook Air runs 24/7 at 90+C. Her laptop is so hot at times from the work she does on it I'm amazed it hasn't exploded. But there you go. Not an issue.

 

[andy9l]

A lot of AMD desktop GPUs can run very, very hot. This isn't a surprise.

I'm just saying that what the rep in that chat is saying is they're essentially all defective.

Maybe you're right, but from my research I haven't seen anywhere online that mentions anything over 95ºC as a safe temperature.

I've managed to take a, quite boring, 4 minute video of the throttling these iMacs suffer from as a result of the excessive temperatures. GPU clock speed dropped from 850MHz to ~760MHz (about 10%) within about 90 seconds of a game at mediocre settings (not even playing). If someone can explain this, please do. I am far from a hardware expert.

I fear your last sentence might be correct. My current, and perhaps naive, understanding of the situation is that this iMac was originally designed for components that give off a lot less heat, in 2012. These 5K iMacs use the same design and cannot provide anywhere near sufficient cooling to the M295X GPU under load. Whether or not this will cause failures is yet to be seen, but it does cause GPU throttling, and you are not getting what you paid for for certain tasks.

Just playing back about 2 minutes of my 1080p/60FPS iPhone 6 video (the one I mentioned earlier) in 'Quick Look' got my GPU to 98ºC and the fans ramped up. That simply should NOT happen on a £2,500 computer in 2015!

http://vimeo.com/116208647

 

[WilliamG]

Maybe you're right, but from my research I haven't seen anywhere online that mentions anything over 95ºC as a safe temperature.

I've managed to take a, quite boring, 4 minute video of the throttling these iMacs suffer from as a result of the excessive temperatures. GPU clock speed dropped from 850MHz to ~760MHz (about 10%) within about 90 seconds of a game at mediocre settings (not even playing).

Video link here: http://vimeo.com/116208647

I fear your last sentence might be correct. My current, and perhaps naive, understanding of the situation is that this iMac was originally designed for components that give off a lot less heat, in 2012. These 5K iMacs use the same design and cannot provide anywhere near sufficient cooling to the M295X GPU under load. Whether or not this will cause failures is yet to be seen, but it does cause GPU throttling, and you are not getting what you paid for for certain tasks.

Just playing back about 2 minutes of my 1080p/60FPS iPhone 6 video (the one I mentioned earlier) in 'Quick Look' got my GPU to 98ºC and the fans ramped up. That simply should NOT happen on a £2,500 computer in 2015!

That last part I agree with completely. I'm not sure what the heck is going on there, but something really seems off about simply watching movies on the 5K iMac in terms of temperatures.

 

[Cape Dave]

Maybe you're right, but from my research I haven't seen anywhere online that mentions anything over 95ºC as a safe temperature.

I've managed to take a, quite boring, 4 minute video of the throttling these iMacs suffer from as a result of the excessive temperatures. GPU clock speed dropped from 850MHz to ~760MHz (about 10%) within about 90 seconds of a game at mediocre settings (not even playing). If someone can explain this, please do. I am far from a hardware expert.

I fear your last sentence might be correct. My current, and perhaps naive, understanding of the situation is that this iMac was originally designed for components that give off a lot less heat, in 2012. These 5K iMacs use the same design and cannot provide anywhere near sufficient cooling to the M295X GPU under load. Whether or not this will cause failures is yet to be seen, but it does cause GPU throttling, and you are not getting what you paid for for certain tasks.

Just playing back about 2 minutes of my 1080p/60FPS iPhone 6 video (the one I mentioned earlier) in 'Quick Look' got my GPU to 98ºC and the fans ramped up. That simply should NOT happen on a £2,500 computer in 2015!

http://vimeo.com/116208647

Amen to that! Cooling is super important. Just because something maybe CAN run at that temp does not mean that it SHOULD EVER run at that temp!

 

[cynics]

Wouldn't it be easiest to find a couple different graphically intensive benchmarking test. The end score should indicate performance vs throttling.

Compare all iMacs from high end non retina models, base retina models to high end retina models.

Here is an interesting thread but what is most curious about it (as a potential retina iMac buyer) are the results. Notice I posted in that thread with my iMac which should be relatively slow. However compared to high end retina models (from those that posted screen shots as clear evidence) is dangerously similar with my iMac running quiet as a mouse (1200 RPM fan).

https://forums.macrumors.com/threads/1835628/

Be nice to find some other benchmarks programs that are graphically intensive for comparison.

 

[WilliamG]

There's something seriously, seriously wrong with the way some applications work with the 5K iMac (in my case, i7/295).

Take for example, YouTube. This video in CHROME at 1080p/60, for example, heats my GPU to about 100C, fans at 2300rpm after not very much time. Crazy! A video!

https://www.youtube.com/watch?v=UtNXO6vHQ2o#t=11

Given my iPhone 6 Plus or iPad Air 2 can do 1080p without exploding, something is going on here...

But in Safari it manages heat much better, though still NOT perfectly. At least my GPU isn't completely frying. Crazy...

In both Chrome and Safari this is using the HTML5 player, so we can't even blame Flash anymore.

 

[Astelith]

Are you sure that your fan control is working properly ?
I got loud fan but I never had temp over 101°C and no throttling in any circumstances, even in Bootcamp with games.
If you have a dirt version of the os the fan speed control may be not working properly, and I've noticed that in windows you need to use a software to make it work or high temp and throttling will happens.

 

[joema2]

...This video in CHROME at 1080p/60, for example, heats my GPU to about 100C, fans at 2300rpm after not very much time. Crazy! A video!

https://www.youtube.com/watch?v=UtNXO6vHQ2o#t=11

But in Safari it manages heat much better, though still NOT perfectly. At least my GPU isn't completely frying. Crazy...

In both Chrome and Safari this is using the HTML5 player, so we can't even blame Flash anymore.

If you examine CPU and GPU activity when playing that video in Chrome on the retina iMac, it is likely using excessive levels of activity. IOW it's not a case of the GPU getting too hot at a moderate level of activity -- rather something in the software stack is causing excessive GPU activity levels which in turn causes higher heat.

Just because both Safari and Chrome both use HTML5 means little in this regard. HTML5 supports multiple codecs, and browsers differ in how they implement this.

Maybe it would be better to use a simple HTML5 benchmark like Fireflies: http://ie.microsoft.com/testdrive/performance/Fireflies/default.html

On my 2013 iMac 27 with GTX-780m, the Fireflies benchmark in a full-size Chrome window (2560 x 1282) does about 28 fps and according to iStat uses about 70% GPU activity. Within about 5 min, GPU temp reported by iStat hits 62C. Fan stays at about 1200 rpm.

Fireflies is a good, easy-to-run test that puts significant (but not 100%) load on the GPU. It would be interesting to see how a retina iMac with M295X behaves running this. It runs OK in Safari and Chrome but doesn't run right in FireFox.

 

[h9826790]

On my 2013 iMac 27 with GTX-780m, the Fireflies benchmark in a full-size Chrome window (2560 x 1282) does about 28 fps and according to iStat uses about 70% GPU activity. Within about 5 min, GPU temp reported by iStat hits 62C. Fan stays at about 1200 rpm.

Fireflies is a good, easy-to-run test that puts significant (but not 100%) load on the GPU. It would be interesting to see how a retina iMac with M295X behaves running this. It runs OK in Safari and Chrome but doesn't run right in FireFox.

Interesting test webpage. Anyway, for Chrome, it seems enter presentation mode will put more load on the GPU. I am not sure if it's V-sync related, but when I ran the test on my cMP, FPS stay at 60.

 

[carlob]

But in Safari it manages heat much better, though still NOT perfectly. At least my GPU isn't completely frying. Crazy...

I ran the video in Safari, got 58C at the most. I don't use Chrome.
I believe most of the issues with the 295 gpu are software related also drivers are not optimized yet. I wouldn't be surprised to see a firmware update and drivers update from Apple in a short timeframe.

 

[carlob]

Fireflies is a good, easy-to-run test that puts significant (but not 100%) load on the GPU. It would be interesting to see how a retina iMac with M295X behaves running this. It runs OK in Safari and Chrome but doesn't run right in FireFox.

Weird results with my retina/295 in safari:

 

[WilliamG]

Weird results with my retina/295 in safari:

Same result here. You can tell that page is HAMMERING on the iMac because Mission Control runs REALLY badly with that page up.

 

[joema2]

Same result here. You can tell that page is HAMMERING on the iMac because Mission Control runs REALLY badly with that page up.

On my 2013 iMac 27, 3.5Ghz i7 and GTX-780m, Mission Control runs fine with the Fireflies HTML test running. iStat Menus shows my GPU at about 70% utilization, but CPU cores are at about 40% each.

So you and Carlob got about 100C on the GPU when running it on your retina iMac with M295X -- interesting.

I just thought it was an easy to run test that stresses the GPU via HTML5 vs Valley and Heaven the use OpenGL. The high-GPU, high-heat behavior is consistent between it and other HTML5 videos retina iMac users have reported. It's easy to reproduce the difference between M295X iMacs and GTX-780M iMacs.

So it's not just hard-core games -- my impression is playing an HTML5 video shouldn't cause that behavior on the retina iMac.

 

[JronMasteR]

I've never seen a gpu getting that hot so quickly...
Something is seriously wrong with these iMacs.
No chip should ever run this hot. The desktop cards are already running extremely hot, 95° on the 290X. But 105° plus?
The cooling system is clearly not nearly able to handle the heat of these gpus.
The AMD R9 290 series are terrible anyway IMHO, their using a insane amount of power and thus getting crazy hot.

This is just ridiculous considering how cool the nvidia chips are running on the older iMacs and also on the rMBP's.

Anyone that can still return their unit should do it and wait for the next update.
This is a very poorly designed iMac. Apple should have waited with this refresh and chosen the 970/980m for it. With these chips, the iMac 5K would have been amazing machines.
With the power efficiency of the new nvidia chips, they could put 2 in.

I'm wondering how long these iMacs will last until they fail...

 

[Fester1952]

Fireflies is a good, easy-to-run test that puts significant (but not 100%) load on the GPU. It would be interesting to see how a retina iMac with M295X behaves running this. It runs OK in Safari and Chrome but doesn't run right in FireFox.

Retina iMac, i7 M295X, running that in Safari GPU got to 105C.
I am often bewildered the things that push the GPU temperature up at times.
I have a Logitech hub based universal remote. I was just adding a device in MyHarmony, and the GPU went to 105C, nothing graphic intensive there!. Exited out of MyHarmony, temp back to normal again.

 

[cynics]

Interesting test webpage. Anyway, for Chrome, it seems enter presentation mode will put more load on the GPU. I am not sure if it's V-sync related, but when I ran the test on my cMP, FPS stay at 60.

Interesting. I found similar performance between Chrome and Safari with Chrome having a pretty consistent albeit slight edge over Safari (1-2 FPS more and 3c cooler GPU).

Both tested at full screen, Safari 2560x1378, Chrome 2560x1368. Don't know if that 10 lines of resolution is what is causing the difference in performance.

Chrome window movement and resizing while Fireflies is running is clearly smoother. Safari is quite the mess.

Scores 1060-1100 FPS 33-35 at full screen max temp with Safari 64c.

 

[steve62388]

I have a Logitech hub based universal remote. I was just adding a device in MyHarmony, and the GPU went to 105C, nothing graphic intensive there!. Exited out of MyHarmony, temp back to normal again.

This is not a Retina iMac issue. I have a mid 2012 rMBP with Nvidia 650m GPU and Logitech Harmony Touch. Exactly the same thing happens to me, start the Myharmony software and my MacBook fans kick into noisy high speed. Exit Myharmony and they promptly spin down again.

I think you'll find it has more to do with Logitech's crappy implementation of Silverlight in the Myharmony app.

 

[AlifTheUnseen]

I've never seen a gpu getting that hot so quickly… Something is seriously wrong with these iMacs.
No chip should ever run this hot. The desktop cards are already running extremely hot, 95° on the 290X. But 105° plus?
The cooling system is clearly not nearly able to handle the heat of these gpus. The AMD R9 290 series are terrible anyway IMHO, their using a insane amount of power and thus getting crazy hot.

This is just ridiculous considering how cool the nvidia chips are running on the older iMacs and also on the rMBP's.

Anyone that can still return their unit should do it and wait for the next update.
This is a very poorly designed iMac. Apple should have waited with this refresh and chosen the 970/980m for it. With these chips, the iMac 5K would have been amazing machines. With the power efficiency of the new nvidia chips, they could put 2 in.

I'm wondering how long these iMacs will last until they fail...

Amen, I desperately wanted something to replace my mid-2010 iMac, yet, this piece of badly designed hardware shall not attack my wallet!

This is a poor design - there may be benefits if designers and marketing specialists control the decisions at apple, but this 5K iMac surely forced the poor hardware engineers at Apple to implement GPU throttling as a sad end-of-pipe solution to make a poor ab-initio-design stable enough to sell them, hoping the eager Apple 'clients' do not notice the flaws. It's already a questionable design if you use notebook parts for a desktop computer but this 5K iMac brings the absurdity to new levels.

The ridiculously thin enclosure of the iMac was designed for much less power consumption / heat production years before. The Apple technologists and hardware engineers showed on the Mac Pro with the triangular thermal core that they are capable. The iMac line is in serious need of this type of engineering genius.

 

[Astelith]

Guys, remember to turn on the fans


Fans in Auto ( Macs Fan Control) Max 101°C



Fans at Max, 91/92° C



Fans at min, 106°C + GPU Throttling @ 6xx MHz