7900 XTX - how much performance does it lose at lower power?

[GrimReaper85]

I can't find this info anywhere on the internet. First reason is that most seem to think power limit -10% is all you can do to limit power.
No, with RDNA3/4 where MPT doesn't work anymore, you can still set the max frequency. I had 7800 XT set to 2500 MHz and power went down from 267W to 225W and with 1030 mV undervolt still 101-103% stock performance.

So what can you expect at 250W, 270W and 300W with 7900 XTX? Probably around 80, 85 and 90% stock (350W) performance?
If that is true (it can't be far off afterall), then here at 1440p it should be between 4070 SUPER and 4070 Ti which consume 220-280W, so 250W is same efficiency:

NVIDIA GeForce RTX 5080 Founders Edition Review

The NVIDIA GeForce RTX 5080 is out now. Priced at $1000 it includes all the new GeForce RTX 50 features and offers good gaming performance. On the other hand, the gen-over-gen performance increase is smaller than expected, but NVIDIA didn't raise their pricing either.

www.techpowerup.com

But these 2 cards cost around 700€ and 7900 XTX is 900€, so 250W doesn't make much sense.

At 300W it should be 4070 Ti SUPER performance at same Wattage, same price, but 24GB of VRAM. And 3080 10GB or tops 4070 RT performance.
I think a very good purchase and way better than these 5080 for 1400€.

If not for the upcoming 9070 XT, I would buy this card in a heartbeat. But I think better RT performance and FSR 4 and most of all better efficiency (300W vs. 350W and same performance, in RT even more difference) are more important than 24GB which you only need for RT and FSR upscaling anyway.


Also another thing I read on Mindfactory (German store) is driver errors, most probably due to unstable GPU and not actual driver problems as this was reported only with 7900 XTX. I had them on 6900 XT also. I also read somewhere that AMD cards are overclocked too far from the factory, I guess only the top models as 6800 and 7800 XT were fine. So lowering frequency should fix that?

 

[Contra]

Sapphire Radeon RX 7900 XTX Nitro+ Review - Maxing out 3x 8-Pin

The Sapphire Radeon RX 7900 XTX Nitro+ comes with the largest factory overclock of all Navi 31 cards that we've tested so far. Sapphire was also very generous with their power limits. During overclocking, with increased limits we were able to max out the 525 W power delivery capability of the 3x...

www.techpowerup.com

Just follow the instructions, except that you can lower the maximum frequency instead of raising it. If you get a driver error when overclocking, then your overclock is unstable, change it

 

[GrimReaper85]

What am I looking, this is OC?

I think on 3DCenter.org they should have an answer. But my German knowledge is like 10%, from high school, I understand it 30-50%, but I always have to use Google translate to write.

 

[Vayra86]

Be aware that a heavy undervolt will not be sustainable once you also activate any kind of RT load, or some other load that pushes heavily on the GPU in DX12. All your DX11 content will run flawlessly with an undervolt. And then you fire up something like Black Myth Wukong and it all falls apart

On my 7900XT I had to go from 1025mv to 1075mv to get stability in BMW. Similar things occur in Cyberpunk with RT on. At that point the only real tweak you've got left is the core clock, and you'll still need to do this per game, with some games being limited to something around the 2300mhz region because the GPU will simply not reach higher and therefore still use all of its alloted board power. That fact alongside the recurring need for Adrenaline to reset your OC entirely at sometimes random moments, makes this quite a hassle. I find myself reapplying my OC every few weeks even if there are no crashes.

Still though I run my card like this most of the time and this doesn't crash anywhere. Peak power is about 290W, but far more often I'll be maxed out around the 250W region with pretty much full performance.

 

[Macro Device]

So what can you expect at 250W, 270W and 300W with 7900 XTX?

At least 5 outta 10 samples can save all 100% performance (= reference model at stock settings) at a 300 W cap. Will definitely lose at least a couple % at 270 W. About 10%, at 250 W. Sweet spot is around 280 to 300 W, depending on silicon lottery. This is without RT.

24GB which you only need for RT and FSR upscaling anyway

Upscaling saves you VRAM. Whilst technically consuming it it also shrinks VRAM usage by shrinking the internal resolution so you have less memory usage.
RT on AMD GPUs is genuinely a joke.

300W vs. 350W and same performance

It won't be the same. 7900 XT, maybe, but XTX is gonna be more productive.

in RT even more difference

Still worse than 3090 Ti. Could be significantly worse because of very low VRAM bandwidth. E-e-eh.

driver errors, most probably due to unstable GPU and not actual driver problems

Usually yes. With 9070 XT reported to be that highly overclocked out of the box... I'm not sure if it won't be worse.

At 300W it should be 4070 Ti SUPER performance at same Wattage, same price, but 24GB of VRAM.

It's brutal how undervolting Ada GPUs is effective. Not completely sure about 4070 Ti Super but I ran a vanilla 4070 Ti at 190...200 W (98% stock performance at ~67...73 % stock wattage). Also, with any RTX GPU, you get access to DLSS, DLSDR, and with 4070 Ti Super, you also can meaningfully enable RT. Additional VRAM is sweet but if you virtually never need more than 16 GB (most games require you to install XXXUHD texture packs for that to happen, or to crank the settings to the very maximum, and yes, at 8K so it's 10 FPS anyway) then what's the point?

Not an NVIDIA fan by any mean but AMD offerings just are even worse in almost any metric.

 

[GrimReaper85]

Doesn't sound like a very good card. So for now 4070 SUPER or 4070 Ti SUPER.

 

[Frick]

Be aware that a heavy undervolt will not be sustainable once you also activate any kind of RT load, or some other load that pushes heavily on the GPU in DX12. All your DX11 content will run flawlessly with an undervolt. And then you fire up something like Black Myth Wukong and it all falls apart

Add to this a card might be heavy game stable but not software with hardware acceleration stable. I learned this when my 6950XT was Very Heavy Game stable but after two hours in Paint.net it crashed and I lost those two hours of work.

Doesn't sound like a very good card. So for now 4070 SUPER or 4070 Ti SUPER.

Nah, it's a good card (unless you consider DLSS/CUDA vital) but you cannot buy cards based on their OC/undervolting potential because that will always be a gamble.

 

[mb194dc]

More like how much more performance can you get at lower voltage.

Some nonsense in the op, re 6800xt has loads of headroom with tweaked voltage boost curve and memory. Will do 20k+ on Timespy GPU and 10k on Timespy extreme GPU with ease

 

[Dr. Dro]

If you're efficiency minded, Navi 31 is not for you. 9070 XT should be out in a couple of weeks if you're willing to give AMD a shot - otherwise RTX 40/5070 Ti for best perf per W.

 

[GrimReaper85]

Of course I am willing to give AMD a shot. 4070 Ti SUPER is already out of stock since yesterday and €100-200 too expensive. And 5070 Ti will be €1000 at very low stock same as 5080 is now at €1400, and 1400€ from scalpers like 5080 is now at €1800.
9070 XT is our only chance to get a good deal.

 

[Dr. Dro]

Of course I am willing to give AMD a shot. 4070 Ti SUPER is already out of stock since yesterday and €100-200 too expensive. And 5070 Ti will be €1000 at very low stock same as 5080 is now at €1400, and 1400€ from scalpers like 5080 is now at €1800.
9070 XT is our only chance to get a good deal.

Keyword, chance. Counting on good pricing on a recently launched GPU in 2025 is quite wishful, regardless of what you're in the market for.

 

[Contra]

The best all-around value for a high-end GPU right now is the 7900xtx. That includes rasterization, llm, UE5 RT, etc., especially if you can get it for $700-800. You don't need all the dlss/fg tricks, but if you want to use them to save power, it works great on it (also named fsr/afmf/fg with frame rate target control). The general consensus is that RDNA4 won't make a huge difference to the core compute units. And the 9070xt is still a much smaller die. If you want dlss/mfg then select NV overprice)

 

[AsRock]

Be aware that a heavy undervolt will not be sustainable once you also activate any kind of RT load, or some other load that pushes heavily on the GPU in DX12. All your DX11 content will run flawlessly with an undervolt. And then you fire up something like Black Myth Wukong and it all falls apart

On my 7900XT I had to go from 1025mv to 1075mv to get stability in BMW. Similar things occur in Cyberpunk with RT on. At that point the only real tweak you've got left is the core clock, and you'll still need to do this per game, with some games being limited to something around the 2300mhz region because the GPU will simply not reach higher and therefore still use all of its alloted board power. That fact alongside the recurring need for Adrenaline to reset your OC entirely at sometimes random moments, makes this quite a hassle. I find myself reapplying my OC every few weeks even if there are no crashes.

Still though I run my card like this most of the time and this doesn't crash anywhere. Peak power is about 290W, but far more often I'll be maxed out around the 250W region with pretty much full performance.

View attachment 384036

Indeed, some games might take 4-8 hours to crash out some much sooner, RDR was the worst as it could be 5 minutes too 5 hours then t be black screen reboot.

You have test loads of games to make sure it's stable, and because you ran some thing like OCCT for 5 hours still don't make it stable.

 

[GerKNG]

under 300W it drops significantly but over 350W it barely does anything.
my 7900 XTXs both do not scale at all at beyond 400W (literally less than ~3% between 350W and 450W)

 

[Vayra86]

Indeed, some games might take 4-8 hours to crash out some much sooner, RDR was the worst as it could be 5 minutes too 5 hours then t be black screen reboot.

You have test loads of games to make sure it's stable, and because you ran some thing like OCCT for 5 hours still don't make it stable.

Just something with 100% utilization and DX12 + mesh shading / RT / other new tech and you can usually see just fine. Its not like I spent hours finding my OC. It was a 10 minute affair Also I'd just work in increments of 0.025mv, starting as low as I could and working my way up. There's not a whole lot of options left then to test. When BMW crashed, I bumped the core voltage by one increment, still crashing, so gave it another, and poof, rock solid.

That said, when you have the proper clock dialed in for game X / Y, it works miracles, the GPU runs cool, is silent, and performs fantastically. At some order of 250W~ 280-300W for the XTX I think you're also rivalling Ada efficiency. At stock they're already not too far apart, after all (some 10%).

under 300W it drops significantly but over 350W it barely does anything.
my 7900 XTXs both do not scale at all at beyond 400W (literally less than ~3% between 350W and 450W)

Core clock seems to scale badly in a broader sense. A VRAM OC is generally more impactful. But I think that's for large part because these are already clocked to their limit with their stock settings. That's why there's so much to play with on undervolting.

 

[MCJAxolotl7]

The best all-around value for a high-end GPU right now is the 7900xtx. That includes rasterization, llm, UE5 RT, etc., especially if you can get it for $700-800. You don't need all the dlss/fg tricks, but if you want to use them to save power, it works great on it (also named fsr/afmf/fg with frame rate target control). The general consensus is that RDNA4 won't make a huge difference to the core compute units. And the 9070xt is still a much smaller die. If you want dlss/mfg then select NV overprice)

Yes, but at least in the US nobody's damn selling any!

 

[GrimReaper85]

I also see since today there are almost none in Germany Mindfactory left, only XFX MERC, I would guess around 10 cards.

4080 retains 95% stock performance (average of latest 5 3DMarks) at 238W, without any OC!, I doubt 7900 XTX can match that. Plus it is easier to power limit.
Though that doesn't help much when they are so expensive (€1500 now) or out of stock, and used ones go for €900-1000.

I just wish 9070 XT will be in stock, pricing doesn't even matter at this point if it will be 10-20% above MSRP.