1600W enough for 2xRTX 6000 Pro BW?

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AutonomousHangOver@reddit

I got 2x 6000 BL workstation edition. With BeQuiet 1600W PC was resetting each time after I load full model to them, despite GPUs throttled to 320W. After I just added spare 850W, situation got better. Funny thing is, that with 1600+850 (both BeQuiet) I could easly add 5090 to this rig and it's all working as it should. So it could be that BeQuiet PSU didn't have enough power to withstand spikes of current being drawn.

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shifty21@reddit

Each PSU should list the max and max sustained wattage on the label. 1600w is the max, not sure what the sustained max wattage would be for that model.

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AutonomousHangOver@reddit

You're right, but in this case I've just seen PSU restart on current spike. 6000s does not honor throttling for transient current draw but for average. Saying this, it is up to PSU quality to deliver even x1,5 - x1,9 current ratings for a couple of hundreds of milliseconds. Maybe it was just too sensitive circuit that monitors draw an prevents brownouts, Idk. Adding a small one helped for now. As I have couple of more GPUs and new case is comming to me, I'll be switching to 3x 2200W PSUs either way. Just have to check which brand will have quality and price in the right spot.

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shifty21@reddit

I'm in the US, with 110v power and a 15 AMP breaker... I can't use 2200w unless I upgrade to a dedicated 220v circuit. I'm assuming you're in the EU if you can just toss 2200w PSUs in 😅

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AutonomousHangOver@reddit

Ah yes, I'm in Poland. Even with that I got 3 phase powerline and decided to put each of PSUs on separate phase on dedicated circuit. I don't want to risk any failures with my rig.

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hainesk@reddit

You also need to check the 12v rail capacity since not all 1600 watts can be allocated to PCIe.

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Arli_AI@reddit

Same experience here. This is the case if you truly max out the GPU like with training. For inference I found its mostly doable with 1600W.

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Mr_Moonsilver@reddit (OP)

Thank you! This adds a new perspective!

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Khipu28@reddit

If it’s a modern PSU with ATX3.0 or better standard it should handle the transient power spikes

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ImportancePitiful795@reddit

ATX3.0 will not handle well the RTX6000s. Because they rely on the information from the PSU (the small pins on the top). Last thing someone should do is run 6000 with ATX3.0.

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Khipu28@reddit

The difference between 3.0 and 3.1 is that the power pins are longer and its less likely to not insert them correctly. The functionality of the sense pins are unaffected by the standard.

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JockY@reddit

The 6000s are either 600W for the Workstation or 300W for the MaxQ. 1200W absolute worst case for the GPUs, but there’s no point in running the Workstations @ 600W unless training because 350W runs at the same speed as 600W for inference. Throttle them to 350W and never think about it again.

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Ok_Technology_5962@reddit

Just set a max wattage output for the gpus. No one needs 2x pro 6000 at full output 250 watt limits and still have pull performance

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Herr_Drosselmeyer@reddit

1600 should be enough, but if you're building a system that expensive, you might as well go for the bigger PSU. I went with this one [https://seasonic.com/atx3-prime-px-2200/](https://seasonic.com/atx3-prime-px-2200/) for dual 5090s and haven't had any issues so far. It's a bit overkill, but hey.

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No_Success3928@reddit

The max q versions can be power limited to 300w fyi, so if wattage is a concern maybe look at those

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Uninterested_Viewer@reddit

Max q is a 300watt card by default. You might be thinking of the workstation edition, which is 600w and, yes, can be power limited as needed.

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Mr_Moonsilver@reddit (OP)

That's what I was thinking, since they cost about the same. Form factor isn't an issue thankfully.

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Mr_Moonsilver@reddit (OP)

Hey, thanks for the reply. I read somewhere the max q version is actually quite performance limited. I can't cite sources but I read a post by someone that explained it quite in depth, and that it's far beyond the 10% performance penalry advertised, especially around batch workloads. This made me consider the workstation edition.

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MitsotakiShogun@reddit

*If* it's exactly the same as the workstation (I don't have both so I cannot test), then llamacpp output tps (tg) is roughly the same at 300W and 600W, but input tps (pp) drops linearly. However, graphics performance also drops a good deal (in my testing a 10% drop happens when you reach ~450W with some (dubious) undervolting, or ~500W without undervolting). Image generation suffers too, with a ~15-20% drop when using 450W (so 75% power).

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itsjustmarky@reddit

I have two RTX 6000 Pro on a 1200W and it is perfectly fine. I have them power limited to 300W and retain 96% of the performance of 600W. I peak at 825W @ 300W and about 1150W at 600W.

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Mr_Moonsilver@reddit (OP)

Thank you for a helpful post. Do you see the performance retain at batch workloads too?

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itsjustmarky@reddit

Yes

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MitsotakiShogun@reddit

It should be fine, but I'm getting the 2200W one for my build. I don't see the point of saving a couple hundred CHF on a build that costs >=20k CHF, it's literally a rounding error at this point. Especially for a build that's meant to be stable (otherwise why go with ECC and workstation?).

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durden111111@reddit

I would trust 1600W with 2 6000s. You aren't going to be running everything at 100% hopefully. Power limits/undervolts etc. I would get wireview pro's as well if you are going to splash out on two 6000s just to be insured against melting.

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Mr_Moonsilver@reddit (OP)

I was thinking about that, but I don't think they fit due to the angled connector they have.

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abnormal_human@reddit

I would do it. I have 4x6000Ada on 1600W on an Epyc Milan system for a couple years and it's rock solid. Also have 4x6000Blackwell Pro on 2x1600W with a 9955WX and no issues there either. I have not tried to "break" either box but in practice I'm almost never utilizing 100% CPU and 100% GPU at the same time. Typically when I'm stressing the GPUs it is for training workloads and while GPUs are pegged, CPU is closer to idle.

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juggarjew@reddit

I have a Corsair HX1500i with a threadripper 9960X and 2 x RTX 5090 Founders (575 watts PL each), everything is on stock settings, no issues running LLM or benchmarks so far. I do no plan to be in a situation where I am maxing out the CPU at 350 watts TDP along with both GPUs. I can always undervolt later if I want. So far so good.

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Mr_Moonsilver@reddit (OP)

Thank you, very reassuring.

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Phaelon74@reddit

Yeap, just use LACTd to undervolt in Linux and off you go.

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1600W enough for 2xRTX 6000 Pro BW?

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29 Comments

AutonomousHangOver@reddit

shifty21@reddit

AutonomousHangOver@reddit

shifty21@reddit

AutonomousHangOver@reddit

hainesk@reddit

Arli_AI@reddit

Mr_Moonsilver@reddit (OP)

Khipu28@reddit

ImportancePitiful795@reddit

Khipu28@reddit

JockY@reddit

Ok_Technology_5962@reddit

Herr_Drosselmeyer@reddit

No_Success3928@reddit

Uninterested_Viewer@reddit

Mr_Moonsilver@reddit (OP)

Mr_Moonsilver@reddit (OP)

MitsotakiShogun@reddit

itsjustmarky@reddit

Mr_Moonsilver@reddit (OP)

itsjustmarky@reddit

MitsotakiShogun@reddit

durden111111@reddit

Mr_Moonsilver@reddit (OP)

abnormal_human@reddit

juggarjew@reddit

Mr_Moonsilver@reddit (OP)

Phaelon74@reddit