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DPete27
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Share Your GPU Undervolt

Thu Feb 16, 2017 12:24 am

There's been some discussion in various threads about undervolting GPUs to cut down on power/heat/noise, so I figured I'd share my findings here and make a place where others can share their results about cutting power consumption without giving up performance

This is a rudimentary guide from my experience undervolting my RX480
First off, there are many power saving options offered in the AMD settings.  "Power Efficiency", Frame Rate Target Control", and "Chill".  As far as I know, unless you enable at least one of these settings, or an in-game framerate target setting, your GPU will simply run at it's max frequency (State 7) at all times in games.
Power Efficiency:  Not 100% sure what this setting does, but I was able to use it effectively in Rise of Tomb Raider to lower power draw by an average of 15W without affecting framerates.  I used that feature while Global Wattman was set to Auto voltage.
Frame Rate Target Control:   This feature allows the GPU to dynamically downclock itself to only deliver a max of the target frame rate.  I have this enabled in global settings to cap framerates at my monitor's 60Hz native refresh rate.  No use in running your RX480 at max clocks to play LoL at 1000fps if your monitor is only showing you 60fps.  This has obvious power saving benefits depending on how un-demanding the game is.  It also effectively serves as a (IMO) more desirable (albeit not quite as consistent) form of VSync because it doesn't introduce added latency.  The downside of FRTC, is that it only works on DX9/DX10/DX11 games so far.
Chill:  Works similar to FRTC, with some added features.  Easier to just point you at TR's article on Chill.  I haven't dabbled with this much, since it seems to apply more to FreeSync monitors.  Worth noting that AMD's Whitelist of games that support Chill is pretty scarce at the moment.

Now, to the undervolting.  To do this in AMD Wattman, you'll go to Global Settings -> Global Wattman and toggle the GPU voltage control from Auto to Manual.  This will populate the GPU core voltages from State 1 to State 7 (these are load states), as well as the memory frequency State 1.  I also have frequency set to dynamic which shows the clock speed at each state.

First you'll want to test for the lowest memory voltage your card can run stable (I used FurMark and Doom-Vulkan to test my settings).  I've found that the memory voltage seems to act as the lower limit of core voltage (ie, if my memory voltage was set to 975mV, the core would receive a minimum of 975mV also, despite core voltage settings being less than 975mV for the frequency being tested).  My RX480's minimum stable memory voltage was 900mV.  My card idles at 300MHz/800mV.

Once you get a stable memory voltage, start by lowering your State 7 core voltage.  Depending on what your particular GPU's advertised boost clocks are, and ASIC quality, will determine what the core voltage can be.  My 1305MHz state is plenty stable at 1030mV for example.  Test your settings for State 7.

Next, set the State 7 frequency and voltage equal to the values in State 6.  When you benchmark (with power saving features off), the GPU will ramp up to State 7.  In order to test the lower States, you'll need to set every State higher than the one you're testing to be equal (ie. if you're testing State 5, frequency and voltage of States 5,6,and 7 need to be the same).  Proceed down the states as far as you like.  I tested States 5-7.

I found that creating an Excel scatter plot of my Frequency/Voltage curve helped visualize what intermediate states should be if you don't want to test for voltage at every state. If you set the Voltage Control toggle back to Auto at any point, there's a good chance your voltage curve will be lost, so it's nice to have a record of what you found stable.

One last thing.  Since I tested in Doom - Vulkan, I found that power saving features like Power Efficiency and FRTC didn't work and my GPU ran in State 7 at all times.  Even 1235MHz on my RX480 @ 1080p and Ultra settings produced 120+fps, which is wasteful on my 60Hz fixed refresh rate monitor.  You can enable game-specific frequency curves by clicking on the game in AMD settings and navigating to Profile Wattman.  

TL;DR, here are the settings I tested stable on my MSI RX480 Gaming X 8G:
Some people like to also reduce maximum frequency to avoid the range of exponential voltage increases needed to maintain higher frequencies than a GPU/architecture is comfortable with (AMD Hawaii GPUs were notorious for being pushed beyond their comfortable range by AMD).  My personal opinion is that I paid for the clock frequency of my card, so I'm not going to give that away.  Hence I'm only doing voltage adjustments and leaving my card's frequency curve alone.
ASIC Quality = 80.1%
Memory Voltage = 900mV at 2000MHz (8GHz effective)
Core Frequency/Voltage = 610MHz/818mV - 910/840 - 1075/880 - 1145/900 - 1190/910 - 1235/925 - 1305/1030.
Power usage as reported by GPU-z: Doom - Vulkan = 135W@1305MHz, 110W@1235MHz. Furmark = ~100W@1305MHz, and ~80W@1235MHz. Auto voltage setting wanted 1150mV for 1305MHz = 130W in Furmark.
[Updated after more testing in the 1190MHz-1235MHz range.]

Share your results!!
Last edited by DPete27 on Mon Mar 27, 2017 10:09 am, edited 3 times in total.
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Re: Share Your GPU Undervolt

Thu Feb 16, 2017 8:16 am

I managed to downclock and downvolt on GTX 1070 to 1708MHz core / 0.825V / 80% power limit from stock GPU boost ~1900MHz core / 1.05V in MSI Afterburner on custom voltage curve. Essentially I'm getting 90% of max stock performance but at 1/2 the TDP, but at the cost of RAM running at full speed wasting power for video decoding for some odd reason which is still something I couldn't manage to solve. It's rather insane how much NV overtuned GP104 and the same reason why I dislike auto overclocking features.
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Re: Share Your GPU Undervolt

Thu Feb 16, 2017 8:38 am

I can confirm that my RX480 runs stable on 1240/975mV but anything below depends on the game. I run the memory at default settings, I don't think it matters much for power consumption and I did get some weird crashes when I tried 950mV.

I had measured the difference in maximum total system consumption to something like 50W (see on of my posts on the subject here: viewtopic.php?f=3&t=118160&p=1325144&hilit=ptsant#p1325866 )

As I reported earlier, anyone with an RX480 should at least try 1240/1000mV for core. If you want more perf, 1300+/1075mV may or may not work.
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Re: Share Your GPU Undervolt

Thu Feb 16, 2017 9:49 am

ptsant wrote:
I run the memory at default settings, I don't think it matters

DPete27 wrote:
 I've found that the memory voltage seems to act as the lower limit of core voltage

My RX480 ran itself at 1305MHz/1075mV on auto at times, so I'd imagine that's a relatively safe bet for manual tweaking.  Other times it would go up to 1125mV.  Good point about measuring "stock" power draw though.  Testing ran late into the night last night, so I did my best to scramble together a forum post before I went to bed.  I'll have to update my original post with that info.  If I get time, I also want to drill into my voltage setting at 1235MHz.  I suspect my voltage setting of 975mV is still a bit conservative for that frequency, but it fit the curve well.
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ptsant
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Re: Share Your GPU Undervolt

Thu Feb 16, 2017 10:02 am

DPete27 wrote:
ptsant wrote:
I run the memory at default settings, I don't think it matters

DPete27 wrote:
 I've found that the memory voltage seems to act as the lower limit of core voltage

My RX480 ran itself at 1305MHz/1075mV on auto at times, so I'd imagine that's a relatively safe bet for manual tweaking.  Other times it would go up to 1125mV.  Good point about measuring "stock" power draw though.  Testing ran late into the night last night, so I did my best to scramble together a forum post before I went to bed.  I'll have to update my original post with that info.  If I get time, I also want to drill into my voltage setting at 1235MHz.  I suspect my voltage setting of 975mV is still a bit conservative for that frequency, but it fit the curve well.

I was unlucky in the chip lottery and got a relatively bad chip quality but I do have a very nice PSU. For an average chip I think 950mV should be doable at 1240MHz. Going below 950mV is probably only possible with the best chips and may not even be completely stable in all workloads.
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Re: Share Your GPU Undervolt

Fri Feb 17, 2017 1:57 am

Not RX 480 but running HD 7970 - 1050 MHZ @ 1030mV currently.
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ptsant
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Re: Share Your GPU Undervolt

Fri Feb 17, 2017 2:30 am

Jigar wrote:
Not RX 480 but running HD 7970 - 1050 MHZ @ 1030mV currently.


That is quite an aggressive undervolt. I ran mine at 1090mV/1000MHz but undervolted at the BIOS. I could go a bit lower but didn't want to risk putting it into the BIOS.
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Re: Share Your GPU Undervolt

Fri Feb 17, 2017 4:02 am

ptsant wrote:
Jigar wrote:
Not RX 480 but running HD 7970 - 1050 MHZ @ 1030mV currently.


That is quite an aggressive undervolt. I ran mine at 1090mV/1000MHz but undervolted at the BIOS. I could go a bit lower but didn't want to risk putting it into the BIOS.


Actually these numbers are set in bios, since recently after 4 years of service my card refuse to run at 1100 MHZ @ 1175mV. Also, i am not playing any demanding games these days and usually playing Dota 2, DOOM or WarHammer 40K which works perfectly fine at full HD resolution. I think i wont mind if my card last me 2 more years as that will make this card my longest serving graphic card (6 years).
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Re: Share Your GPU Undervolt

Fri Feb 17, 2017 6:32 am

Jigar wrote:
ptsant wrote:
Jigar wrote:
Not RX 480 but running HD 7970 - 1050 MHZ @ 1030mV currently.


That is quite an aggressive undervolt. I ran mine at 1090mV/1000MHz but undervolted at the BIOS. I could go a bit lower but didn't want to risk putting it into the BIOS.


Actually these numbers are set in bios, since recently after 4 years of service my card refuse to run at 1100 MHZ @ 1175mV. Also, i am not playing any demanding games these days and usually playing Dota 2, DOOM or WarHammer 40K which works perfectly fine at full HD resolution. I think i wont mind if my card last me 2 more years as that will make this card my longest serving graphic card (6 years).


Mine also served for a very, very long time and I would probably have kept it if I didn't want FreeSync. It still works in a secondary PC, in fact.
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Re: Share Your GPU Undervolt

Fri Feb 17, 2017 8:20 am

Need to double-check when I get home but I think I'm running a Gigabyte RX480 8GB reference board at 1275MHz/925mv and I'm limited in my undervolting by the Memory not the GPU.

Sure, you can set your GPU to 900mv but if your GDDR5 is set to 1000mv then all the tools report the GPU voltage as 1000mv.
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Re: Share Your GPU Undervolt

Wed May 10, 2017 5:46 pm

Just an update to this thread, the old RX480 wasn't quite stable in the long term at 925mv - I think it was actually the VRAM that needed more juice in a couple of games so when I came to test this RX580 I noted that I'd been running 1275MHz @950mv all this time.

This RX580 (Sapphire Nitro+) seems to be very similar. I've stuck it on 1300MHz @1000mv for now and will perhaps update this post if I feel inclined to search for the optimal speed at the VRAM's lowest stable voltage.
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Re: Share Your GPU Undervolt

Fri May 12, 2017 6:53 am

I have an Asus Dual RX 480 O4G (4GB) overclocked with afterburner to 1340Mhz core /1850Mhz memory. I get stable 1340 core in Withcer 3. No crashes at all. Max temp is 83c with fan speed max 76% (custom curve). Default voltage. Powelimit +20.

I have a big room with large windows and room temp goes upto 50c and lowers slowly to 28c after I turn on aircon. In winters max GOU temp was 75c.

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Re: Share Your GPU Undervolt

Fri May 12, 2017 9:24 am

Maning. I assume you're on auto voltage then? What does the core voltage read in GPU-z when the GPU is loaded?
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Re: Share Your GPU Undervolt

Sat May 13, 2017 9:12 am

DPete27 wrote:
Maning. I assume you're on auto voltage then? What does the core voltage read in GPU-z when the GPU is loaded?

It goes upto 1.313V at full load.
 
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Re: Share Your GPU Undervolt

Mon May 22, 2017 8:59 am

manig wrote:
It goes upto 1.313V at [1340MHz].

You'd probably be able to run 1340MHz @ 1.100 mV if you manually set voltages. Probably start and see if you can do 1340MHz @ 1.150V first and back down from there. See my first post in this thread for guidelines. Setting a manual voltage curve will likely save you a BUNCH of watts/heat. Probably close to 50W.
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Re: Share Your GPU Undervolt

Mon May 22, 2017 12:48 pm

DPete27 wrote:
manig wrote:
It goes upto 1.313V at [1340MHz].

You'd probably be able to run 1340MHz @ 1.100 mV if you manually set voltages. Probably start and see if you can do 1340MHz @ 1.150V first and back down from there. See my first post in this thread for guidelines. Setting a manual voltage curve will likely save you a BUNCH of watts/heat. Probably close to 50W.

Sorry its not 1.313v but 1.131v at 1340/1850.
 
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Re: Share Your GPU Undervolt

Mon May 07, 2018 10:26 am

Resurrecting an old thread, because I've spent around three hours trying to get the very best out of my RX Vega 56 (Sapphire, reference model). I'm using Unigine Valley as a stress test, but the key to maxing out the GPU load is to use high-resolution/utlra/8xAA, pause the animation on a tree-heavy scene with wind and rain. The result is 100% full GPU load with no dips in GPU demand from scene changes (confirmed independently by Unigine, Wattman, and GPU-Z). Once I have a GPU-bottlenecked scene running at 1440p, I can put out a couple of results, using the default "Balanced" profile as a baseline.

It should be noted that My HBM2 runs at 960MHz/867mv and even if I pump waaaaay more voltage into it, I still start to see artefacts/corruption at 965MHz. No matter how low I set the voltage in Wattman, the minimum voltage the HBM2 will operate at is 867mv, and therefore that is the lowest possible VDDC for the core too. I've settled on a stable HBM2 overclock of 940MHz which is 25MHz lower than the point at which corruption appears and so far I've been gaming for around 5 today without any hiccups.

Factory stock settings (the baseline):
BIOS1, default 'Balanced' profile - 800MHz HBM2/Auto voltage/Auto clock/Auto temps
Performance = 72.9fps = 100%
Avg. clock = 1387MHz = 100%
Avg. fan = 2315RPM = 100%
Avg. Watts = 175W = 100%
Avg. VDDC = 952mv = 100%

AMD's idea of an efficient BIOS profile:
BIOS2, 'Power Save' profile - 800MHz HBM2/Auto voltage/Auto clock/Auto temps
Performance = 69.9fps = 96%
Avg. clock = 1278MHz = 92%
Avg. fan = 1885RPM = 81%
Avg. Watts = 135W = 77%
Avg. VDDC = 900mv = 95%

The lowest I can go:
Custom profile - 940MHz HBM2/867mv/1402MHz core/75-80C
Performance = 75.8fps = 104%
Avg. clock = 1296MHz = 94%
Avg. fan = 1888RPM = 81%
Avg. Watts = 133W = 76%
Avg. VDDC = 868mv = 91%

In summary, I don't seem to have much control over the undervolt, or the resulting core speeds. If you don't want to use the BIOS2 'Power Save' profile, your best bet for tuning Vega is to do what I did, without the trial-and-error:

  1. Find out what the minimum HBM2 voltage is (by dropping it to something stupidly low like 700mv, and then recording the actual minimum voltage)
  2. Set that voltage for 'State 6', 'State 7', and 'Memory Voltage'
  3. See how high you can push the HBM2 clocks before corruption
  4. Dial it back a few percent for stability
  5. Set power limit to +50% because you don't want that interfering with clockspeeds
  6. (Optional) Monitor the average fan speeds at full load, and then set the target speed to 15% higher, and minimum speed to 15% lower.
This last step keeps the cooling more constant and avoids the noisy spikes in fan noise that happen when the default fan settings let the temps climb too high, resulting in a fan-control 'panic' burst that's well in excess of your target speed.

I'm a little underwhelmed, really. The 'Power Save' profile on BIOS2 is almost as low as the card can operate already, and most of the performance gains from Vega appear to be in the HBM2 overclocking, which (hopefully) anyone with a Vega card already knows. Still, with a bit of tweaking I managed to get a 4% performance boost over stock settings whilst using 24% less power and making a reasonable noise reduction, and it's nice to be running a Freesync GPU+monitor combination again (It's totally worth it just for the mild 60>75Hz refresh rate bump)
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Re: Share Your GPU Undervolt

Mon May 07, 2018 12:16 pm

I had great luck undervolting my 1050Ti MaxQ GPU. It's running at a steady 0.9V and maintains 1700+ Mhz at that voltage. Of course, my laptop is more thermally limited and I may reduce clocks to lower temps and fan speeds.
 
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Re: Share Your GPU Undervolt

Mon May 07, 2018 12:21 pm

Chrispy, could you supply HBM2 frequency in each "profile"? I was a little confused at your 960MHz stated initially, then 940MHz at the end of the paragraph.
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Re: Share Your GPU Undervolt

Mon May 07, 2018 12:50 pm

It's 940MHz in my custom profile, otherwise the two AMD profiles are 800MHz.

960MHz is the absolute limit of my HBM2. For all I know that's not long-term stable, so I've choosen to dial it back a little bit just so that I'm not running it right at the raggedy edge, if you know what I mean. Since 940MHz is also what the Vega64 runs at, it's a reasonable assumption that most cards are stable at this HBM2 speed;

I don't think they made "Vega56" and "Vega65" cards separately, I think they made "Vega" cards and then binned them and BIOSed them based on which ones passed muster as "Vega 64"s, which is why all Vega56 reference cards run on Vega64 BIOSes without exception. Sadly the core count seems to be hardcoded to the unflashable SoC ROM so you can't magically enable the disabled CU too see if it was binned for defect or voltage reasons :(

Also, I should clarify that my disappointment with Vega is relative. I'm really pleased with it as a singular data-point, it's just that I had access to a lot of RX480's and I managed to find one that clocked from 1.2V down to 925mv and that allowed me to get something like 99% stock performance for a 39% power reduction. That thing was sick.
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Re: Share Your GPU Undervolt

Mon May 07, 2018 1:37 pm

Chrispy_ wrote:
Resurrecting an old thread, because I've spent around three hours trying to get the very best out of my RX Vega 56 (Sapphire, reference model)...


I think getting the "best" out of any Vega 56 Reference model is by putting the 64 BIOS on it... unless you are trying to run it a minimal power usage. Depending on noise tolerance or replacement with liquid cooling the Vega 56/64 can be undervolted and overclocked up to around 1530Mhz GPU & 1050-1100Mhz HBM2 I think I was running about 1000mv GPU & 975mv HBM2. I'll have to check when I get back home.

I run mainly lower GPU clock 1150 & 1100 HBM with something like 975/925 I think mostly (my 2xVegas mine while I'm not playing) and with those settings I can play a game of Age of Mythology: Titans and mine at the same time... hash rate sometimes dips a little and mining ethereum with Claymore will sometimes hang, but I still like to "play".
 
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Re: Share Your GPU Undervolt

Mon May 07, 2018 2:08 pm

Yeah, I *am* trying to minimise noise/power - that's the point of an undervolt thread; "How cool/quiet can you go without giving up performance?"

I've tried a 64 BIOS but it doesn't affect the minimum voltage I can put through the HBM2, nor does it let me clock the HBM2 any higher than 965MHz. I'm guessing I was dealt a poor hand in the silicon lottery. At ear-splitting 4800rpm on the fans with the 64 BIOS, I can get 1550Mhz or so, but IMO the noise just isn't worth it. My 1440p 75Hz monitor just doesn't need that much performance, but my ears *do* need peace and quiet ;)
Last edited by Chrispy_ on Mon May 07, 2018 2:10 pm, edited 1 time in total.
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Re: Share Your GPU Undervolt

Mon May 07, 2018 2:10 pm

Chrispy_ wrote:
it's just that I had access to a lot of RX480's and I managed to find one that clocked from 1.2V down to 925mv and that allowed me to get something like 99% stock performance for a 39% power reduction. That thing was sick.

My XFX RX480 does 1288 MHz (OCed by XFX) at mV of 1.045 unfortunately the DDR5 doesn't want budge from stock even though their Samsung brand.
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Re: Share Your GPU Undervolt

Mon May 07, 2018 5:02 pm

Chrispy_ wrote:
Yeah, I *am* trying to minimise noise/power - that's the point of an undervolt thread; "How cool/quiet can you go without giving up performance?"

I've tried a 64 BIOS but it doesn't affect the minimum voltage I can put through the HBM2, nor does it let me clock the HBM2 any higher than 965MHz. I'm guessing I was dealt a poor hand in the silicon lottery. At ear-splitting 4800rpm on the fans with the 64 BIOS, I can get 1550Mhz or so, but IMO the noise just isn't worth it. My 1440p 75Hz monitor just doesn't need that much performance, but my ears *do* need peace and quiet ;)


Minimizing Noise/Power may be the your point of this thread... but there are plenty of V56/64 owners that use under-volting to allow higher clocks on same or less power than the default BIOS.
I look as it as "insurance" so when I upgrade to something like 3440x1600 (hopefully at 100 or 144Mhz in the near future)

As far as the Vega 56 is concerned I haven't seen it able to get over 965-1000 Mhz on stock bios.... without the 64 BIOS, neither of my 56s would go over 965Mhz. With 64 BIOS 1100Mhz is no issue at all.

I decided to go water to get rid of all the fan noise. My Voltages are :
-cvddc 925,925
-mvddc 925,925
-powlim -20,-20
both cards can even run 1400 Mhz on the GPU with these setting, although some hard core gaming might require more juice. I use these settings mainly for mining and AoM:T (which is not an graphically intensive game)
Image

And here is another Vega56 with 64Bios on Air (in the same PC, soon to be watercooled also)
Image
 
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Re: Share Your GPU Undervolt

Mon May 07, 2018 5:47 pm

Hmmm, I'll try reflashing a 64 bios back onto the P1 switch. I put it back to the stock BIOS because it wouldn't let me run the HBM at a lower voltage, hence no benefit to fan noise.

I've yet to find a game at 1440p that doesn't benefit from HBM2 speed increases. Potentially 1100MHz core and 1100MHz mem would be faster than 1300MHz core and 940MHz mem - and this is of interest to me because the core clock (and voltage) accounts for the lion's share of the power consumption (and thus heat/noise)
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Krogoth
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Re: Share Your GPU Undervolt

Mon May 07, 2018 8:46 pm

I must have a good sample of Vega 64.

It purrs along at ~1650Mhz/1000Mhz HBM with 950-1050vm core and 1000 vm memory while consuming around 200-250W. The GPU never goes above 75C with ran running at ~3000RPM.
Ivy Bridge i5-3570K@4.0Ghz, Gigabyte Z77X-UD3H, 2x4GiB of PC3-12800, Sapphire RX Vega 64, Corsair CX-600 and Fractal Refined R4 (W). Kentsfield Q6600@3Ghz, HD 4850 2x2GiB PC2-6400, Gigabyte EP45-DS4P, OCZ Modstream 700W, and PC-7B.
 
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Re: Share Your GPU Undervolt

Wed May 09, 2018 6:38 am

I flashed the 64 BIOS again last night and although you're right in that it let me run the HBM higher (crashes at 1020MHz instead of 965MHz), it also substantially raises the minimum power draw and harms the performance/Watt.

At the same voltages and speeds as the 56 BIOS for P6, P7, and HBM2, the 64 BIOS used significantly more power, probably because the 64 BIOS uses 0.95V base, instead of the 56 BIOS'es 0.90V, and power use increases exponentially with voltage increases.

In summary, the quietest option for me is the 867mV setting on a 56 BIOS with a 945MHz HBM2. The core clock hovers around 1295MHz regardless of whether I set higher values because that's all it can do whilst adhering to the minimum 867mV restriction. Unlocking the extra 75MHz of HBM2 with the 64 BIOS is not enough extra performance to justify the raised voltages. Perhaps this would be different if my HBM2 hit 1100MHz or something like that, but 5-6% more HBM2 performance is not worth a 15-20% power increase.

Admittedly, if I didn't care about fan noise, the 64 BIOS would net me a few extra percentage points, but THG did some extensive power/efficiency testing with Vega and the sweet spot is somewhere very close to the BIOS2 power-save profile, which would mean a core-only power draw of around 145W. Since that power draw happens at around 1200MHz on the core with the 56 BIOS, it seems that I am already running faster than the efficiency sweet spot, but it's close enough that the power/heat/noise don't change much.
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