6900XT undervolting advice

Shingyboy

Shingyboy

Shingyboy

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Joined
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Location
Birmingham
Hello everyone,

So I have a 6900XT phantom gaming and I saw a video where undervolting can provide some performance benefit, I don't understand that works. So in the AMD Radeon software where you can tune it what type of voltages overclock for the GPU and RAM can you guys reach with this card just out of interest. Do you have any tips for sweet spots for stability and fan curve for good temperatures whilst also not being too noisy?

I put my power limit to maximum which was 15% and voltages to 1120 as it kept crashing otherwise, left fan curve default and not sure what to do with it.
 
Ok so I think you have some things mixed around in your head so I will start with the basics. Power = Voltage x Amps , this means if you reduce the voltage you will use less power at the same clocks and therefore the gpu will run cooler. Temps are not usually the limiting factor on RDNA2 but it is useful. By upping your power limit you are needing more power hence potentially more V which is why you saw instability.

You really should reset to defaults and then only reduce the voltage until you start seeing crashes, once that happens up it by .25mv and it should be stable at those clocks.

TBH just watch this video , I am sure Jay explains it better than I can.

www.youtube.com

The CORRECT way to gain FREE FPS with any AMD GPU

Check out the first controversial video here! https://www.youtube.com/watch?v=-KvkVumbgvwLearn more about the Viewsonic XG321UG Mini-LED HDR panel at https:/...
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Shingyboy said:
Hello everyone,

So I have a 6900XT phantom gaming and I saw a video where undervolting can provide some performance benefit, I don't understand that works. So in the AMD Radeon software where you can tune it what type of voltages overclock for the GPU and RAM can you guys reach with this card just out of interest. Do you have any tips for sweet spots for stability and fan curve for good temperatures whilst also not being too noisy?

I put my power limit to maximum which was 15% and voltages to 1120 as it kept crashing otherwise, left fan curve default and not sure what to do with it.
Click to expand...

At stock speeds 2550MHZ, I undervolted from 1.2V to 1.70V. Any lower and it crashes.
 
GilgameshIQ said:
At stock speeds 2550MHZ, I undervolted from 1.2V to 1.70V. Any lower and it crashes.
Click to expand...

There must be some serious misunderstandings around this subject or everybody is drunk with typos.

If you go from 1.2v to 1.7v you have not undervolted at all, you have increased the voltage by 0.5v which is a very significant amount and not something I would recommend. If you want to undervolt then whatever the stock voltage is has to be decreased, if the stock voltage is 1.2v and you reduce that to 1.1v then you have undervolted.
 
Haz123 said:
There must be some serious misunderstandings around this subject or everybody is drunk with typos.

If you go from 1.2v to 1.7v you have not undervolted at all, you have increased the voltage by 0.5v which is a very significant amount and not something I would recommend. If you want to undervolt then whatever the stock voltage is has to be decreased, if the stock voltage is 1.2v and you reduce that to 1.1v then you have undervolted.
Click to expand...

You are correct. From 1.2 to 1.07v
 
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GilgameshIQ said:
You are correct. From 1.2 to 1.07v
Click to expand...

That makes much more sense. Every chip will eventually crash when you reduce the voltage. Once you find the crash point up the V bu 0.25mv and it will most likely be stable, there may still be some instances where it will crash.

If you were to leave the V at 1.1 that would be approx and 8% decrease so 8% less power and heat generated by the gpu. Not 8% reduction in total board power but it is significant.
 
Haz123 said:
That makes much more sense. Every chip will eventually crash when you reduce the voltage. Once you find the crash point up the V bu 0.25mv and it will most likely be stable, there may still be some instances where it will crash.

If you were to leave the V at 1.1 that would be approx and 8% decrease so 8% less power and heat generated by the gpu. Not 8% reduction in total board power but it is significant.
Click to expand...

Yeah mate, I noted my junction temp came down by about 10 degrees. My power draw is roughly now around 200W. Previously it was 280-300. I'll take a video and share it.
 
I set my 6900XT:
power: -10
Max Freq: 2000
Voltage(mV): 1090 (can goto 1060 for most games but some(LEGO) crash)

I run at 60Hz + V-Sync so don’t need to clock high to get good performance.
HWInfo64 says power is 60-100W when a game is running, don’t think that is total board power but it’s much lower than at default.
 
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Why have I gone from 6600 all the way up to 6900xt?! Mainly driven by VRAM future-proofing in a crazy GPU market that I think I wanna go big and not bother looking at the state of it all for 5+ years .

I am held back by 550w Gold PSU otherwise I'd be happy picking up the 2nd hand CeX offering and not contributing to the over inflated offerings
 
Tinfoil-G305 said:
Why have I gone from 6600 all the way up to 6900xt?! Mainly driven by VRAM future-proofing in a crazy GPU market that I think I wanna go big and not bother looking at the state of it all for 5+ years .

I am held back by 550w Gold PSU otherwise I'd be happy picking up the 2nd hand CeX offering and not contributing to the over inflated offerings
Click to expand...

It funny you think CeX are not helping to inflate prices. Your buying ex mining cards at about +20% on used prices
 
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