PSU Needed for Dual High End GPU's
MrRogerSmith
Posts: 88
Hi all. I am presently using a 3080ti and I am considering adding a 3090. My PSU is 850w 80 plus gold.
Can anyone advise whether I will need to upgrade my PSU, or would this be adequate? I'm not tech savvy.
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Do you have 1 hard drive or 8 hard drives ? Do you have 1 screen or 4 screens ? etc. etc.
Your question is basically impossible to answer for anyone outside of your computer room.
Check graphic cards max power usage on their respective official constructor's webpage.
Check your power consumption : https://outervision.com/power-supply-calculator
And calculate this + that + this + that = XXX watts. Only you can answer that question.
"Adding" a 3090 in a system that already has a 3080ti ? ... Pretty sure you can't use NVlink with that. Asymmetrical SLI has never really been an option. I also doubt you'd be able to stack VRAM. Use one or the other ? Probably. Use both, even with Blender... I doubt it.
And... I thought 3080Ti had no SLI connectors whatsoever ?
Did you do some reading before ?
SLI 3080ti : nope
SLI 3090 : yes
Assymetrical SLI 3080ti / 3090 .... : what ?
There are various calculators out there:
https://outervision.com/power-supply-calculator
https://www.newegg.com/tools/power-supply-calculator/
I used to use PCPartPicker's one but I can't seem to reach it now:
https://pcpartpicker.com/forums/topic/316-power-supply-calculator
Thank you both, the calculator was just what I needed.
Pretty sure with DAZ you don't need SLI or anything-iRAY will just use the GPUs sitting in your computer. You can't stack VRAM, but you can increase rendering speeds.
I have a 3090 and a 1200W power supply but I'm concerned if even that would be enough if I tried to add a 4090, lol.
The only GeForce RTX cards with NVLink are 2070 Super, 2080/Super/Ti and 3090/Ti, VRAM stacking is only possible with NVLink (between identical cards) and even then only for textures, not for geometry.
One can have multiple cards and DS will use then to speed up the rendering, using the ones that have enough VRAM to fit the scene in.
It's worth pointing out that the OP never mentioned SLI or anything of the sort, and that was an assumption on the part of responders. SLI is also not the only way one benefits from having multiple GPUs, so adding a 3090 to a system with a 3080ti is a perfectly valid choice, so long as the OP understands what it will and will not do for them.
MrRogerSmith,
Figure out your PS requirements now, and wait until October to buy:
https://www.tomshardware.com/news/wait-to-buy-a-new-high-end-gpu
Thanks for the tip!
Also, if you actually get this to work, please report back here! I originally bought a 1200w power supply with the idea of running a 1080Ti/3090, but got kind of nervous about how much power my 3090/10850k were drawing, so put aside that project.
I wouldn't go with anything less than a 1500 watt PSU. I know a while back prior to getting my new system, I was thinking of getting 2x 3090's and remember one of the custom shops telling me that a 1500 watt PSU was necessary in order to maintain system stability when using both cards together. The thing is these RTX cards can have really really short power spikes that far exceed their TDP and may cause the system to shut down if the PSU cannot handle it. A 3080Ti isn't very far below a 3090, so I would be sure to get at least a 1500 watt if your system is going to have both a 3080Ti + 3090 rendering together. You might get away with a 1200 watt depending on what all components the system is using, but I think it would be safer to go higher rather than find out later that you need a higher wattage PSU.