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

Did a quick check of my GPU idle temps:

48-49 idle with two screens running (I've got a random 23" screen 1920x1080 which Im using for static info as I work)
40 idle with one screen running

Ran a couple of different apps (browser, mail, messages) with no change.


I've also noticed that the GPU temp spikes for no apparent reason. I left a game idling for 10-15 mins and wandered away. GPU temp around 98-99. I came back to find the fan going @ 2300 rpm with the GPU sat at 105. It had been sat there for several minutes.......but it wasn't doing anything to justify that increased activity as there was nothing new on screen. Really strange.

All of this is in OS X by the way. Since I need to learn how to do things the apple way I'm staying away from boot camp and other things.

Astelith said:

...the heatsink can't cool the GPU enough and so reaching the 108°C ...

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That leads again (and again and a.....) to the question: Why haven`t they set the target limit to lets say 90°C ? The card is still fast enough for almost everything.. even throttled by 20%

CrankItUp said:

That leads again (and again and a.....) to the question: Why haven`t they set the target limit to lets say 90°C ? The card is still fast enough for almost everything.. even throttled by 20%

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I'm not an engineer, maybe 100°C is the best compromise for this architecture to operate with a minimal heat system dissipation and fan noise.
But honestly this is not something I (we?) care about, some unit cooler than others is, if I pay premium money to have something and then I discover other users with a better built unit... I will be seriously pissed.
I'm lucky to be the "good reference" but this is unfair to the others.

blufrog said:

The amount shown in the iFixIt photo is excessive and will create serious problems.

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The iFixIt photo in this thread showing thermal paste is not a picture of the Retina circuit board. If you compare the actual Retina board in their teardown to this picture they are quite different, the Retina board doesn't have all those orange things (whatever they are).

IFixIt regularly recycle photos. Of course the Retina paste might be applied in the same manner but this photo doesn't prove it.

MrLeek said:

Did a quick check of my GPU idle temps:

48-49 idle with two screens running (I've got a random 23" screen 1920x1080 which Im using for static info as I work)
40 idle with one screen running

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That's getting warm enough for just idling.

What is the ambient temp?

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steve23094 said:

The iFixIt photo in this thread showing thermal paste is not a picture of the Retina circuit board. If you compare the actual Retina board in their teardown to this picture they are quite different, the Retina board doesn't have all those orange things (whatever they are).

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Iron chokes (they're in the power regulation circuitry for the CPU).

IFixIt regularly recycle photos. Of course the Retina paste might be applied in the same manner but this photo doesn't prove it.

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Good point, but I'd say highly likely. It's not something that would change between systems - it's "only" another heat-sink with thermal paste.

CrankItUp said:

A) The difference between 2700 RPM/ 2300 RPM and 1200 RPM @ full load is 3°C - so what?

B) If the fan is auto-controlled it wont ever reach 108°C - so you wont notice heavy throttling anyway

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Thanks a lot for the tests. Regarding A), there is also the additional difference between heavy throttling (down to 600ish MHz?) vs. only minor throttling (less than 10% below max boost frequency).

The fan doesn't seem to be the bottleneck for GPU cooling, this seems quite clear. I would guess that there would not be a difference between 2300 and 2700 with load just on the GPU.

thundersteele said:

...there is also the additional difference between heavy throttling (down to 600ish MHz?) vs. only minor throttling (less than 10% below max boost frequency).

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Thats what i figured out. As soon as 108° is reached (only reachable with 100% GPU load and fans manually set to the lowest rpm) heavy throttling kicks in. In the "normal" case (auto-controlled fans) u wont ever notice a speed loss in any applications.
The minor throttling - yes you might say that- is still sufficient to keep the GPU at a maximum of 105° and a not noticeable performance loss - its a balancing act, but what the heck - it works

Lowering the target temp by 5-8°C could lead to satisfying results for everyone also without a noticeable performance loss. I think in the best case there will be a SMC update in a few months but i dunno.. via a firmware update everything is possible

PS: Everything will be worn out anytime (including me) so the 5k... and i guess almost everyone has apple care with that machine.. 3 years warranty - what else to say

Just to chime in, my M295X reached 108C in Windows during gaming.

The fan should have been at 2700rpm since the CPU was throttling too. I didn't check that though as I'm not particularly Windows savvy. It could have been 2300rpm. It was damn loud, either way.

andy9l said:

Just to chime in, my M295X reached 108C in Windows during gaming.

The fan should have been at 2700rpm since the CPU was throttling too. I didn't check that though as I'm not particularly Windows savvy. It could have been 2300rpm. It was damn loud, either way.

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But didn't you just return your riMac just a couple of pages ago, did you?

Anyways, I would recommend installing Macs Fan Control on the Windows side. You can set it automatic so that it monitors GPU temp and fan starts to kick in when 60 C is reached and the max temp it tries to keep the GPU is 90C.

This way the fan control is automatic and on the desktop fan is spinning on the minimum 1200rpm, but on the games you get very fast to 2700rpm, and to achieve the maximum cooling potential (instead of 2300rpm). Also on Windows 10 Astelith reported that fan control doesn't work properly on default, so this may also be the reason for 108 C temp and massive throttling, if the fan is simply not spinning properly on Windows on default.

I have tested a few games, both on Windows 10 and OS X (trough Steam, both) and the maximum temp I am getting is 106 C. I am not happy with it, but if this won't cause noticeable trothling and Apple Care for 3 years should cover for GPU meltdowns, I may have to live with this.

I also must correct myself. I have now played Tomb Raider (2013) on both Windows and OS X. GPU temp gets up to 106 C, but there seems to be no noticeable framerate drop even after longer gaming sessions. (It's funny that I am even able to run Tomb Raider on OS X on 5k resolution, though the frame rates are horrible )

I believe my earlier bad experience with Bioshock Infinity is related to drivers and/or sofware - I have not so far seen any noticeable frame rate drops or micro staggering on the other games. Testing continues...

ioxakoyba said:

But didn't you just return your riMac just a couple of pages ago, did you?

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Sorry, I should have been more clear - this 108C temperature I speak of was back in January. Windows 8.1, playing Guild Wars 2 or Americas Army: Proving Grounds (either caused it).

I did indeed return my i7/M295X iMac early January after two separate Apple tech guys told me the temperatures weren't safe.

For examples of how thermal paste alone can harm operating temps, this was an interesting read:

http://www.anandtech.com/show/8227/devils-canyon-review-intel-core-i7-4790k-and-i5-4690k

andy9l said:

I did indeed return my i7/M295X iMac early January after two separate Apple tech guys told me the temperatures weren't safe.

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Did you get this in writing?

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

blufrog said:

For examples of how thermal paste alone can harm operating temps, this was an interesting read:

http://www.anandtech.com/show/8227/devils-canyon-review-intel-core-i7-4790k-and-i5-4690k


Did you get this in writing?

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I got one of them screenshot and I posted it here: https://forums.macrumors.com/posts/20571824/

The follow-up email was from 'Apple Technical Support' and I got the same advice on another occasion prior to this screenshot - albeit on the same day.

The email states that I have two options: return, or take in-store and 'resolve the issue'. I opted for the former.

Just had a very interesting conversation with Apple Tech.

Basically they had this to say:

* iMacs generally do run hot
* iMac 5k runs a bit hotter than the other models generally
* Some individual iMac 5k run very hot, and that should it be an issue there are things they will do (e.g. replace the fan/heatsink)
* One tech said that max operating temp was 105 deg. C
* A senior tech is in the process of sending me tech specs on the GPU

I advised them of a potential manufacturing defect, and I strongly urged them to elevate it up the chain to be examined, which they said they would.

They weren't aware of any failures due to the thermal issue (as yet).

They said that there had been issues with earlier generation MBP whereby Apple were doing a recall, and even refunding people where they had previously been charged for repairs.

They also issued me a case number, despite not even owning a unit yet.

blufrog said:

I advised them of a potential manufacturing defect, and I strongly urged them to elevate it up the chain to be examined, which they said they would.

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I love it how you advised and urged Apple. I'm sure they notified Tim Cook!

Sorry for this, couldn't help it. I don't want to sound harsh, but I don't think they will do anything based on a customer's advice. This is just something the support team would say - "of course we'll look into it sir", and stuff like that. The truth is a huge amount of planning, organisation, supplier deals, etc. went into designing and making any product that it goes beyond individual or group feedback. I don't think average people can even fathom the scope of production when it comes to such large corporations.

They have entire teams dedicated to analysing post-launch statistical data from the stores and service providers, hardware and financial experts, etc. Who knows - maybe it is, actually, more cost efficient to just have a replacement program down the line and fix that 1% of iMacs that overheat in a few years than to change anything in the way they manufacture them.

In other words - they may or may not do something if they themselves determine certain things are faulty and personal opinion of customers won't do anything. Unless you get, like 100 000 people to write them on the same issue and alert the internet media, so they do something as a part of their PR strategy (and only because of that).

So, should we contact Apple with concerns and issues? Of course. It does affect things in the long run. Just, for the sake of sanity, don't give Apple advice

ROFL.

Don't think I'm that nieve. Just reporting what I was told as someone they knew was looking to buy vs. had a unit already.

andy9l said:

I got one of them screenshot and I posted it here: https://forums.macrumors.com/posts/20571824/

The follow-up email was from 'Apple Technical Support' and I got the same advice on another occasion prior to this screenshot - albeit on the same day.

The email states that I have two options: return, or take in-store and 'resolve the issue'. I opted for the former.

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Would be interesting to know how they comment on that fact that every 5k 295 will reach that high temps?? According to their expressions - every sold 5k 295 is faulty... do you have their names? Confronting them with that facts.. i d love to see their faces.. and more to know how they ll state theirs position on this..

I do have their names, but I'm not going to put them on here.

This conversation was had in early January. Their advice might have changed since then now there is a wider understanding of the expected/safe temperatures.

andy9l said:

I do have their names, but I'm not going to put them on here.

This conversation was had in early January. Their advice might have changed since then now there is a wider understanding of the expected/safe temperatures.

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i dont expect you to go public with their names .. but i would appreciate confronting them with their old statement and if their assessment of the situation is still the same? ... and if changed - why? According to what? Were they clueless?

If there is a wider understanding of the expected/safe temperatures as you say, why dont you buy the 5k in the same config you had again? It seemed to run within its specs..

CrankItUp said:

If there is a wider understanding of the expected/safe temperatures as you say, why dont you buy the 5k in the same config you had again? It seemed to run within its specs..

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Simple - a personal disagreement with advertising performance that is only really achieved for a few seconds.

The i7 CPU and M295X GPU are hamstrung by the 5K iMac cooling system. The cooling is not sufficient for the components, so when under sustained load they both throttle to avoid overheating. Tests online show that they throttle by up to 15%. I don't agree with this, so I returned my iMac.

I was also annoyed with the significant increase in fan noise in comparison with my maxed 2010 27" iMac, whilst doing the same tasks.

All that being said, I fully appreciate that it's a great machine for a lot of people. If the issues I've mentioned above do not affect/bother a user, then said user should not worry about their 5K iMac.

andy9l said:

Simple - a personal disagreement with advertising performance that is only really achieved for a few seconds.

The i7 CPU and M295X GPU are hamstrung by the 5K iMac cooling system. The cooling is not sufficient for the components, so when under sustained load they both throttle to avoid overheating. Tests online show that they throttle by up to 15%. I don't agree with this, so I returned my iMac.

I was also annoyed with the significant increase in fan noise in comparison with my maxed 2010 27" iMac, whilst doing the same tasks.

All that being said, I fully appreciate that it's a great machine for a lot of people. If the issues I've mentioned above do not affect/bother a user, then said user should not worry about their 5K iMac.

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I understand this in principal, but that said, I'm a video editor who plays games as well, and without monitoring I haven't noticed any throttles. I have noticed increased fan speed, which I'm just about dealing with, but I don't think this throttling has been perceptible to me running Divinity: Original Sin at 3k 'ultra' setting, or Borderlands 2 (can't remember the setting, but I'm pretty sure it was maxed out).

tmorterlaing said:

I understand this in principal, but that said, I'm a video editor who plays games as well, and without monitoring I haven't noticed any throttles. I have noticed increased fan speed, which I'm just about dealing with, but I don't think this throttling has been perceptible to me running Divinity: Original Sin at 3k 'ultra' setting, or Borderlands 2 (can't remember the setting, but I'm pretty sure it was maxed out).

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Funny thing is in this post there's a wrong usage of the word "Throttling", system used in old architectures where usually a card has 3 "P states" and a thermal event trigger the jump from one to another cutting the frequency by more than 60%, the M295X can dinamically adjust the frequency in a very gradual way to control Temperature or Power Draw Load, even in tough situations the frequency drop is minimal and not "eye naked" percieved.

I think I said this like 10 times in this thread

WilliamG said:

NO! The M295X is an inferior card at 1440p than the GTX 680MX was at 1440p.

Anyone reading this: The M295X is just not good enough. If I hadn't already sold my 2012 iMac with GTX 680MX, I'd probably return this system. Yes, the Retina display is amazing, but next year will probably be a 980M or newer variant, and I'll just sell this iMac.

Apple screwed this one up. I had a feeling they had all along.. *sigh*

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Totally agree on this statement.... I can't wait to sell mine too. Everything is so laggy but the screen is beautiful indeed.

marcel500 said:

Totally agree on this statement.... I can't wait to sell mine too. Everything is so laggy but the screen is beautiful indeed.

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99% The refresh will be with a probable M395X, if so, the Nvidia version will be 2016, and I will sell mine for that one.

But why comparing the two at 1440p ? If you have 5K resolution why using a lower one ?

marcel500 said:

Totally agree on this statement.... I can't wait to sell mine too. Everything is so laggy but the screen is beautiful indeed.

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Can you give an example of this lag?
I agree, and will sell mine based on the heat - but I don't understand statements like this. Even with the throttling bringing down by 15%, this thing is still like 10% faster than previous models. It is not a slow machine with a nice display, it's a quick machine with a nice display that sometimes happens to get a bit hot under heavy load. I haven't experienced any lag or perceptible issues other than fan noise and heat (by observing a monitor).

I think the "lag" is more related to the Yosemite driver / coding issue. Not really hardware hardware related.