The Apple Keynote? Their website? Sure, they use the clever wording "up to", but they sure try to give the impression that it will perform much better than it actually does. It isn't exactly false advertising, but not far from it.
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AMD Radeon R9 M295X Core Clock Throttling, Heat, and Performance
- Thread starter Fenn
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The Apple Keynote? Their website? Sure, they use the clever wording "up to", but they sure try to give the impression that it will perform much better than it actually does. It isn't exactly false advertising, but not far from it.
Prove that it doesn't reach it's potential. Just because it throttles back under certain conditions doesn't mean that it doesn't operate at its designed level of performance. The CPU does the same thing. If it gets too hot, it throttles back, but it can certainly operate at it's designed specification when conditions allow it. Apple said that it can operate at up to 3.5 teraflops. Do you know that it doesn't? There are enough benchmarks showing showing excellent performance for a variety of different tasks that I'm confident that it is performing up to spec. It even has beaten an 8-core Mac Pro with dual D700s in at least two benchmarks that I've seen. As much as people would like to use these for gaming, that's not what Apple builds them for.
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What exactly did they say that is not true?
Further update:
Did some more Diablo 3 testing, and it turns out there's a glitch with this game and the M295X GPU, where if the frame-rate is limited to 120 fps in the settings (as it was by default), for some reason the ACTUAL framerate sticks to 57fps (confirmed with FRAPS). Very weird. Untick that option, and the frame rate locks to 60fps when vsynced. Good.
Performance is definitely superior to the GTX 680MX in this game, as I've been able to maintain 60fps with all settings on high (including shadows, a real killer) at 2560x1440 and 3200x1800. 4K 60fps is possible, but not *always* guaranteed depending on what's going on on the screen.
So yes, the M295X is throttling. Whether it affects the game will completely depend on how close to 60fps you are. If you're running a game, and it's vsync'ed to 60fps but is capable of running at e.g. 90fps, you're not going to notice the frame drops since the Retina iMac runs at a maximum 60hz/60fps max at all times and drops to numbers above that won't be seen.
Now, if you have a game that is just hitting 60fps, you might see the frame-drops which manifest as stutter when the GPU core clock throttles. Now that's a far bigger deal. Of course, any games that run below 60fps to begin with means just frame drops further below that..
*sigh*
I'm really surprised at Apple. The GTX 680MX, to my mind, was revolutionary in the All-In-One space. It ran cool, was easily overclocked, and NEVER throttled. The M295X is a massive step back. Hitting 106C after several minutes of gameplay, as it does easily in my iMac is just... staggering. It sort of feels a bit like the iPad 3. The screen was amazing, but the rest of the internals just weren't ready for primetime.
Did I love the iPad 3? OH yes. That screen made it worth it. And it's the same thing here. Just... that uneasy feeling that Apple will make the Retina iMac right in fewer than 12 months is cause for (at the very least financial) concern.
Did some more Diablo 3 testing, and it turns out there's a glitch with this game and the M295X GPU, where if the frame-rate is limited to 120 fps in the settings (as it was by default), for some reason the ACTUAL framerate sticks to 57fps (confirmed with FRAPS). Very weird. Untick that option, and the frame rate locks to 60fps when vsynced. Good.
Performance is definitely superior to the GTX 680MX in this game, as I've been able to maintain 60fps with all settings on high (including shadows, a real killer) at 2560x1440 and 3200x1800. 4K 60fps is possible, but not *always* guaranteed depending on what's going on on the screen.
So yes, the M295X is throttling. Whether it affects the game will completely depend on how close to 60fps you are. If you're running a game, and it's vsync'ed to 60fps but is capable of running at e.g. 90fps, you're not going to notice the frame drops since the Retina iMac runs at a maximum 60hz/60fps max at all times and drops to numbers above that won't be seen.
Now, if you have a game that is just hitting 60fps, you might see the frame-drops which manifest as stutter when the GPU core clock throttles. Now that's a far bigger deal. Of course, any games that run below 60fps to begin with means just frame drops further below that..
*sigh*
I'm really surprised at Apple. The GTX 680MX, to my mind, was revolutionary in the All-In-One space. It ran cool, was easily overclocked, and NEVER throttled. The M295X is a massive step back. Hitting 106C after several minutes of gameplay, as it does easily in my iMac is just... staggering. It sort of feels a bit like the iPad 3. The screen was amazing, but the rest of the internals just weren't ready for primetime.
Did I love the iPad 3? OH yes. That screen made it worth it. And it's the same thing here. Just... that uneasy feeling that Apple will make the Retina iMac right in fewer than 12 months is cause for (at the very least financial) concern.
anyone else noticed that wow on bootcamp (win 8.1) throttled and was like max half the fps (around 30) but there was no heat/fan noise in return?
it's throttling more than 50% down.
will try out on mac now. not sure if I should now be happy that I got the fan noise resolved but a crappy fps (even with 1080p) and a graphics card that used max. 50% of its potential. could have bought the m290x instead, would surely be faster now.
apple messed up big time. I demand an official statement or call back.
it's throttling more than 50% down.
will try out on mac now. not sure if I should now be happy that I got the fan noise resolved but a crappy fps (even with 1080p) and a graphics card that used max. 50% of its potential. could have bought the m290x instead, would surely be faster now.
apple messed up big time. I demand an official statement or call back.
so the consesus is:
heat problems with GPU running windows for everybody?
no heat problems with GPU running OS X except for those who received a bad machine (which they should have exchanged?
(I could live with that scenario, as windows gaming is not really on my agenda)
heat problems with GPU running windows for everybody?
no heat problems with GPU running OS X except for those who received a bad machine (which they should have exchanged?
(I could live with that scenario, as windows gaming is not really on my agenda)
I should stop checking this forum. This stuff is all over my head, but I do know that I played Civ V for an hour on my RiMac and the fan was going like crazy, enough to notice. Something I never once noticed in 5years on my 2009. Reading through this thread now has me thinking I was not making a mountain out of molehill - what I felt was excessive heat/fan was indeed.
So to be clear... You guys are only complaining about heat and fan noise on the M295X, right? The M290X should run cooler and quieter, even while gaming in boot camp?
I mostly ask because I still have time to cancel my order (M295X) and to get the lower end gpu.
I mostly ask because I still have time to cancel my order (M295X) and to get the lower end gpu.
It seems to be perhaps select applications or maybe even select iMacs. I have no complaints about my 295x iMac. Yes, during graphic intense games, I can hear the fan if I'm not wearing headphones but it isn't particularly loud to me. And my system seems to stay fairly cool. I haven't used an app to see how warm my internals are though, this is just touching the back of my iMac while during graphically demanding games.
Nobody really knows, right now. I'd say go with the M295X since it *should* be better than the M290X. Worst case scenario you send it back.
Noise is subjective. I don't think of the iMac is particularly noisy when under load and fans whirring, but it's certainly not as quiet as yesteryear's iMacs since they could do quite a bit of gaming without making a sound.
funny considering my rMBP sounds like a jet engine trying to take off when I'm playing a game on it
And the noise is a very quiet sound to me on my RiMac but could be the comparison between my laptop and it.funny considering my rMBP sounds like a jet engine trying to take off when I'm playing a game on it
Yes, the rMBP under load is much, much noisier. The iMac sounds more like a rushing of air, whereas the rMBP sounds distinctly like a "noisy" (subjective as that is) fan.
as a follow up - I couldn't care less about the noise of the fan, it's the implication it's machine is getting too hot and in short order (2-3 yrs) will have a major failure because of
Applecare will take care of any failures, and if there's any design issue you know Apple will take care of it as they have done with previous design flaws. Only time will tell if this is the case. These AMD cards run hot even on the desktop PC side.
Ah! Very interesting! Either you have a defective fan or you are spinning up way into the 2000s of RPM.
On the i5/M290X it's impossible to rev the fan past about 1900 RPM (you just can't generate that much heat), at which point it sounds exactly like the rMBP (I have one too).
No. I haven't experienced any real gaming issues with the iMac. Yes, all games have to played at 2560x1440 and in one of the games (Crysis 3) I had to choose "High" instead of "Very High" to get frames to near 40.
I won't call that an issue...
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Partly correct... GPU temp @ 105c when gaming under Windows is real. I feel this is only a problem if it adversely affects gaming performance. Which even in a fast first-person-shootout didn't. So it's not a problem imho.
Long term effects to other components? Will only know long term... AppleCare is a must I think
I have been working on benchmarks for around 50 games and apps over the past week; a continuation of some of the work I did when the 2012 680mx iMacs were released two years ago. I am comparing performance on a myriad of metrics across the 2012 and 2014 fully loaded iMac models including release driver performance versus mature driver performance versus overclock performance at 2560x1440 and 4k/5k resolutions.
I seem to have hit a stumbling block that I cannot resolve and figured I would ask here for help before I post my results. While the 4k/5k performance in bootcamp and OS X isn't as bad as I thought it would be, the M295X iMacs are performing nowhere near where they should be, especially when it comes to 2560x1440 resolutions. There have also been several instances in which I experienced micro stutters that randomly dropped the framerate and performance to almost half of what it currently was for a split second. In fact, in a dozen or more tests, the M295X actually performed worse than the 680mx at standard clocked speeds. Literally an actually decrease in performance for something that should be blowing a two year old card out of the water.
However, I seem to have come across an issue with the Core clock throttling itself long before it actually should be. Everywhere I look it appears that the stock M295X is intended to start throttling at 105°C and until then, with all of the power options on Max, should run at an 850mhz Core clock. However, with a clean Win7 install, the M295X starts throttling itself literally seconds after use and almost as soon as it hits 70°. I can manually watch this using any of the various Core/Memory/Usage/Temperate apps in windows and you can see a perfect Cosine curve in the Core clock as it starts fluctuation in my case between 720Mhz and 762Mhz. (I have included a quick photo below). The clock always starts out at 850 Mhz, so I know these aren't underclocked, but I cannot find a way for the life of me to lock the clock at 850 or disable PowerPlay (which seems to be AMD's temperature based throttle.) The higher the temperature gets, the lower the clock runs, which makes this an absolute PITA for repeat benchmarks and my numbers are all over the place.
I would like to confirm this is also an issue under Yosemite, is there a GPU tool which can show a visual graph of clock speed against temperature that anyone knows about? I looked and the best I could find are just generic lists of core/memory speeds and GPU usage/temperate, but nothing that can show Core throttling.
I don't mean to be alarmist, but I have a feeling that these M295X iMacs may have a lowered temperate curve for enabling throttling, and if this is the case, we are getting nowhere near the performance that we should be getting. Losing over 100Mhz core clock is a huge hit to performance, not to mention as the clock throttles, the micro stutters that can manifest are extremely annoying.
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. Out of 6 generations of iMacs, 3 mac pros and 2 G5's, I have never had a computer that has hit 104°C after 7 minutes of playing a game or rendering 3D and this new iMac shocks me. I seriously question the longevity of these machines and from an engineering standpoint, nothing on the market right now is designed to run over 100°C continuously without failing. Once you add in dust, ambient heat during a non-winter season, and months of use, I would be surprised if these machines lasted longer than a couple years without essentially burning themselves out. We can debate the 'dream' 980MX vs. M295X all day, but Apple chose to get to market with a Retina iMac and the only option was a card substantially hotter than what it should be. The entire AMD 290 line has had heat as a controversy since their release last year. The problem is that the thermal envelope on these cards is too hot for the cooling that this iMac form factor has to offer. If the GPU sits at 104°C while the card is oscillating between 720Mhz and 762Mhz we know that there is no way in heck that we are going to get a natural 850Mhz core clock out of these cards. Even if we do find a way to stop the card from throttling and lock it at 850Mhz, it will likely far exceed the 105°C temperature and bring about instability. This is why I fear this issue has nothing to do with drivers and is probably hardcoded into the card BIOS.
I do not want to spoil anyone's fun; the screens on these iMacs are the best I have ever looked at bar none and an absolute dream to work on. Just the brightness and color contrast alone from not having a visible LCD gate separating the pixels is gorgeous. People with needs that won't tax the GPU won't have any issue to deal with and will LOVE this machine and its breathtaking screen. But heat and the throttling I have experienced is a big problem for anyone wanting complete performance. As it stands, is the screen worth a GPU that is only 3-5fps better than a stock 680MX, and worse than an overclocked 680MX? My heart is breaking, I would have paid anything for a 980mx
I quickly browsed through the pages of posts thus far and haven't seen anyone discussing the boost idea. If I was mistaken and this has been talked about, then apologies.
Essentially, since the HD7000 series (the R2xx series came after), AMD has implemented a hardware based core clock control based on both TDP and temperature. When you are taxing the GPU, the GPU will throttle itself to keep the TDP in check of whatever published maximum figures are. You can change this to some degree with the Catalyst control center by changing the power control slider to say, + or - 20%. This is true at least for discrete AMD cards since the HD7000 series on the PC side. I'm not sure if this option is even available for All-In-Ones like the iMac. Usually changing this to a positive number increases the average time the GPU spends in the higher clock rates, and vice-versa the other way around. You can also even go so far as to hard-code the BIOS (*modify the bios*) to have a slightly different TDP and clock rates, and lower the operating voltage to hit a sweet spot for your particular card. Again, I don't think this option is possible for the iMac, although the control center thing could be possible with driver updates. To recap, the GPU's clock depends on how much load the actual GPU is under, not just thermals. This is a flexible and according to Anand, a high-dynamic range way to power and performance configuration, something we see far more commonly in the tablet/phone world.
Lastly, it is unfortunate that AMD and Nvidia uses two different schemes to accomplish the same ultimate goal, which is to lower the TDP while keeping the AVERAGE performance of the card at a certain level. Nvidia advertises a certain minimum frequency while AMD advertises the max frequency, so in the end, if you bought AMD's target frequency, you can expect that most of the time, the card will hit nowhere near that frequency, since it is TDP constrained. Nvidia will sell you a minimum frequency the card will operate at, and it will boost higher sometimes under some load. Most seems to prefer Nvidia's marketing approach. Either way, that's the future of dynamic range in computing performance. Ever wonder how the new GTX980 and 970s have such a low TDP figure ? It is all in the power control. The cards will burst for short periods, the integrated performance divided by time will always reflect the TDP figure of that card. This is not without faults. For one, the algorithm isn't perfect, and neither are the drivers. You get micro-stutter and real stutter. The GTX970/980s do have this, as well as occasional bursts outside of its TDP range (this is worse and more dangerous) according to reviewers. Hopefully those issues are ironed out in the latest drivers.
I suspect the stuttering you are seeing can be fixed with a driver update. Of course, the tight constraints inside that iMac isn't doing the GPU a lot of long-term good either. Most of what you are seeing are not thermally related throttling save for extreme benchmarks.
Yes, it is the same for me as well. Even if GPU-Z/MSI is reporting 105c, the case behind is cool.... only vaguely warm where the vents are.
This is with gaming for an hour at end. Which isn't this machines forte right?
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+1 thanks for clearing that up.
Not defective. The rMBP is much noisier under load. There's a simple reason for. The iMac had a larger fan thus sounding a little more like air and less whiny/high-pitched.
No. But what do you mean by "issues"? If I play intensive graphical games on it I can get the fan going because of the GPU. If I do a whole lot of video rendering / hugin processing / FCPX stuff I can get the fan going because of the CPU. This is part of the design of the riMac. Fan noise doesn't worry me in games as I have the volume up anyway. Fan noise doesn't worry me when I'm rendering as I am likely to have music going on in the background anyway.
Games run amazingly smoothly considering the number of pixels they're throwing about. If they get too slow or laggy (with more modern or complex games) I can drop the detail levels down a bit, or in extreme cases drop back to 2560x1440. Same as I would on any computer.
I have not successfully managed to run games smoothly in Windows bootcamp as I've only got Windows 10 installed there (and it's about to be deleted anyway). I can, however, run a fair number of less demanding games under Parallels in either XP or Windows 10, far more than I could on my rMBP under Parallels 8. So that's a good thing.
I don't have a copy of Windows 8.1 and am not interested enough in it to be bothered paying for a license.
I really wish Apple had just continued with the x80m GTX line. The m295x ranks lower than a 970m GTX, PLUS it's a $250 upgrade. That's $100 premium over the 680/780 upgrades the last two years. I've never been a fan of AMD GPU's, and the benchmarks and experiences people are having with the m295x is disappointing. I really hope they return to NVIDIA next year.
true. mine is just 3 days away from delivery. but now I think about waiting for the next revision next year ....