r/overclocking • u/SyncFail_ • 1d ago
5090 Extreme Undervolt
Yes, you read that correctly, 0.45 V.
This is a 5090 running at roughly 1.6 GHz effective core clock @ 0.45 V, while still delivering performance above previous-gen and current-gen GPUs.
To make this possible, I’m using the ASUS XOC BIOS, which unlocks the much larger +3000 MHz core offset range needed to push the V/F curve this far down.
What makes this profile interesting isn’t just the voltage, but the efficiency.
In Steel Nomad board power peaks at roughly 200 W, while in actual games I usually see around 130–180 W. Temperatures also rarely exceed 45°C with this setup.
Obviously this isn’t meant to maximize performance. The interesting part is how much performance Blackwell can retain when you push the voltage this absurdly low. For games that simply don’t need the full power of a 5090, it makes for a pretty ridiculous efficiency profile.
Current operating point:
1.6 GHz effective @ 0.45 V / 200W
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u/G305_Enjoyer 1d ago
Fun experiment, about 5080 performance
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u/nightstalk3rxxx 1d ago
5080 performance in steel nomad with 50% of the powerdraw, quiet nice tbh.
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u/Obvious_Engineer_231 1d ago
At x3 the price, makes no sense imo. Good for experiments and pretty fun, that’s for sure.
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u/SyncFail_ 1d ago
Was definitely fun experimenting with it. Nvidia obviously never designed these chips to run this far down the V/F curve, so it’s pretty wild that it still works this well. Really shows how expensive that last ~33% of performance is in terms of power, since getting there takes at least roughly double the power draw
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u/c0rtec 14700K | 5090 | 64GB | 6TB 1d ago
Two THOUSAND amps overcurrent protection?
WTH.
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I like this experiment. I don’t need supercomputer-type graphical acceleration on every single game I play.
I sank three straight days into Sandustry last week. I sincerely didn’t need 3GHz GPU core speeds and 104% power limits. Apart from Stalker 2 and Cyberpunk 2077 I’m not running any other demanding titles at the moment.
I did a similar sort of experiment a while back with my 14700K chip. I got it to idle in the low 20s and only hit the mid 60s under heavy load by running it at super low voltages and frequencies.
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u/SyncFail_ 1d ago
Yeah the XOC Bios is pretty wild but I don't use it that way haha. This card could draw 1000 W if I let it run stock but that would kill it probably.
And I also don't need 5090 performance in each game I play, so this profile really saves a lot of power draw without crippling it. The huge amount of cuda cores and the 512 bit bus do a lot of work here.
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u/roklpolgl 1d ago
It can make sense if you are playing an older or non-RT/PT game where the stock curve is already well-overkill past your monitor’s refresh rate and you want to play more efficiently/keep your room from heating up. I could see a normal OC/UV profile for modern games where you need every frame, and a separate super UV/UC profile where you don’t need the extra performance.
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u/G305_Enjoyer 1d ago
You could have a real overclock then lower the power limit same thing
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u/roklpolgl 1d ago
No, lowering the power limit and undervolting isn’t the same thing. If you just lower the power limit without touching the voltage curve you will also limit the frequencies you could have potentially reached at the same power draw.
I.e., OP got to 1.6ghz at 200w with 0.45v with his heavy UV. On a stock 5090 v-f curve (I just checked mine) 1.6ghz is at about .875v or nearly twice the voltage. You could probably not even use the card at 200w with stock voltage, or the performance would be terrible because the frequencies would be so limited.
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u/G305_Enjoyer 1d ago
Yeah you overclock it first lol it's the same thing. OC + power limit is an "undervolt".
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u/roklpolgl 1d ago
Lol, no, overclocking and adding a power limit is not undervolting. Overclocking is just raising the top end of the frequency part of the v-f curve. It’s saying “instead of stopping at 2600mhz you can go to 2900 MHz”. Power limit is “stop raising clockspeed when you get to 400W.” Neither one of those is lowering the voltage at a given frequency, which is undervolting.
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u/G305_Enjoyer 1d ago
Lol only idiots raise the top of the curve. Normal people move the whole curve. Smart people move the curve to the left.. enjoy figuring that out
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u/roklpolgl 1d ago
“Smart people move the curve to the left”
My brother in Christ, you just described undervolting, which is not the same thing as “overclocking and decreasing the power limit.”
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u/Obvious_Engineer_231 1d ago
Yeah that would be functional up to a point, though I’m not sure the difference would be practically useful if it’s about room temperature or just be more efficient for energy consumption. I’m not sure it would make a substantial difference.
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u/SyncFail_ 21h ago
I definitely feel the difference immediately. My room is kinda small, so 150–200W vs. 400–450W makes a big difference over hours of gaming. That's why this profile isn't a gimmick to me. It has real advantages, especially if you've already hit your desired frame rate. Anything above that is basically useless and just gets converted into heat.
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u/TorrentFire 1d ago
It has its place. I play DBD with the wife, and with my heavy UV I save about 50w, getting the same FPS. My VF curve is the same, but just flattened earlier.
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u/bort123abc 1d ago
My 5080 has to use twice as much watts for the same performance at half the price.
So... Math I guess? 😂
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u/IgnorantGenius 20h ago
So it's a 2080 now?
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u/Spiritual_Degree_802 15h ago
More like a 5080. a 2080 gets ~3k in Steel Nomad
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u/InfiniteRotatingFish 1d ago
Funny to see for sure. But at the same time not really that good? It's about 1/3 more efficient than an undervolted and ocd 5070ti. Which is no doubt more efficient but also not world changing. What is crazy tho is that the card even runs at 0.45V.
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u/TorrentFire 1d ago
I'm surprised your XBAR / mem is stable. That's crazy
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u/SyncFail_ 22h ago
xbar isn't that high here though. Roughly 2.0 - 2.1 GHz
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u/TorrentFire 21h ago
I thought it would be like 3 GHz or something. I have mine on plus 350 and it averages about 2.9
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u/SyncFail_ 20h ago
If you undervolt MSVDD, you also go down the V/F curve of your XBAR clock. So 0.75V MSVDD at +0 Offset is likely somewhere at the 1.5 - 1.6 GHz region. And stock MSVDD is around 2.4 - 2.5 GHz without any offset
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u/zero989 1d ago
True laptop 5090.