Only 1 GPU utilized when 2 is present

[stupendousman_dk]

Playing around with Vantage and seeing how much of an frametime improvement i can get, if i put two 3090's in a workstation, instead of 1.
However i cannot meassure any difference in frametime and it seems Vantage is not utilziing both GPU's.



Using the newest studio Nvidia Driver 546.01 and manually tried selecting both GPU's inside Vantage, they are recognized.

What am i doing wrong?

[npg]

Task manager is not very reliable for GPU utilization. Try with GPU-Z. The supposedly idle GPU is also hot ...

[stupendousman_dk]

Okay thanks - in GPU-Z i see something of a concern, GPU-0 draws a maximum of 180 watts while GPU-1 draws 340 watts. Could there be some power issue crippling one of the cards (brand new 1600 wats PSU) ? Bad connection maybe, will try changing the pinout-cable to PCI-express with a new one.

Have made tons of tests and I can measure a 25 sec. frametime with one gpu and 16 sec. frametime on two GPU's in another scene... So i guess it does works!

Thanks

[npg]

I doubt there is a hardware issue. More likely the load is uneven. Note that if a denoiser is active this significantly changes the load profile on the primary GPU (for example, the AI denoiser uses tensor cores, etc). The app tries to balance the rendered pixels between the two devices to utilize them close to maximum (taking post processing into account). To rule out problems with one of the GPUs just configure Vantage to use only one then the other (requires app restart) and compare the load. When both are active try disabling the denoiser to see how this affects load and power usage. Also, if the balance is not good, changing the scene in any way (i.e. resetting the sample accumulation, for example by moving the camera) will make the app recalculate load factors and change them if necessary.