Originally posted by Eudyptula
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AMDGPU Linux Driver No Longer Lets You Have Unlimited Control To Lower Your Power Limit
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Originally posted by cb88 View PostSetting power limits too low generally doesnt' break hardware... what it does do though is cause it to be more likely to have errors... which nobody wants to spend time tracking down errors because people tuned their GPUs too low.
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Originally posted by M@GOid View Post
I was doing that experiment myself. 2 1080p monitors (via Displayport), 144 and 120Hz. But in my case, If the first one is set to 144Hz and the second to 60Hz, the idle power stays in the minimum. But my card is a RX6600 (from Sapphire), not a RX6800.
My 3440x1400 seems to be the culprit here, nothing helps.
I guess it's not the end of the world, every single light bulb in the house used to be 40-65W and now they are 5-7W, there's always something somewhere that can be done better or gets worse. Also when the screens sleep it goes back to 8W. I don't expect it to be ever fixed actually, as it seems to be a choice made to reduce flickering risks.
Also it's not all nvidia gpus that are immune to it, and it seems fixed for the most part in the 7XXX series despite an atrocious start at 100+W idle. I'm waiting for next gen at least to upgrade, anyway, spending hundreds to save a few bucks per year would be dumb.
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Originally posted by Anux View PostHow does that work? How would a lower TDP produce errors? And why wouldn't you get errors when you reduce the max frequency which is allowed by AMD?
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Originally posted by skeevy420 View Postlowering the TDP could send fewer volts for a given frequency state
some states could be lowered by up to 100mv and others by none before crashing would occur.
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Originally posted by Anux View PostTDP limits the selection of available FID/VID pairs (dependent on your current current draw) but doesn't alter them.
People are talking about undervolting because of the formula I shared above, since power scales quadratically with voltage and linearly with other variables, undervolting is the most effective way to lower power draw.
BTW, if I were to participate in the mailing list, what I would say is that the patch is correct. The driver is not the place to mess with this kind of stuff anyways, of course if you really want to you can patch the driver, bit IMO what you should do is patch the bios of your card, this is what I do, my card even has a switch to change from bios A to B, so if I mess up there is always a known good version accessible.
This is what vendors expect. AMD should not be braking their partners expectations.
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Originally posted by DumbFsck View Post
This is exactly what the patch is solving. Before the patch, setting TDP to go lower than specified "created" new values for FID or VID so that the tdp target could be reached. And now it doesn't.
I never heard of any automatic under volting in such cases. If there were room to automatically under volt (same FID but lower VID) why wouldn't that be the standard the card get's delivered with instead of running it with a higher voltage? Isn't the whole point of those FID/VID pairs to tune the card from AIB and deliver it with thoroughly tested values?
On my current RX 480 I have 7 power states (FID/VID pairs) that are predefined by the AIB. When I lower the power limit to it's minimum some of the highest pairs won't get selected (dependent on workload), but still on idle it selects the lowest pairs without altering any of them and uses much less power so there clearly is much room to lower the power limit even more.
You should clearly be able to reduce the power limit until your locked at the lowest state (I think 600 MHz at 0,85V in my case) and then still get lower with throttling. Although at this point the card would be unusable slow, but when I return to standard settings it would work just like ever with no hardware damage.
People are talking about undervolting because of the formula I shared above, since power scales quadratically with voltage and linearly with other variables, undervolting is the most effective way to lower power draw.
BTW, if I were to participate in the mailing list, what I would say is that the patch is correct. The driver is not the place to mess with this kind of stuff anyways, of course if you really want to you can patch the driver, bit IMO what you should do is patch the bios of your card, this is what I do, my card even has a switch to change from bios A to B, so if I mess up there is always a known good version accessible.
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