Combining GTX 1080 Ti and RTX 3080 on Asus Z490-A

[waldob]

Hi Team - I have a motherboard with tow graphic cards slot. Can Vray use both 1080 Ti and my new RTX 3080 on the same motherboard?

Thank you.

[Joelaff]

Yes, I believe so, but you will run into issues if you use the bucket render mode. The bucket size with GPU is fixed and very large, and in our testing you always end up waiting for slower cards to finish the last bucket. Chaos is reported to be working on this Last Bucket Syndrome (LBS), at least for CPU, I think for GPU as well.

Homogeneous cards shouldn’t have much trouble, but this is a big limitation as far as we are concerned.

[waldob]

Hi Joe - ok thank you. To clarify this will not be beneficial at the moment for me? It will not render faster with the two cards. On your roadmap when do you think of resolving the LBS problem?

[Joelaff]

Oh, I don't work for Chaos. I am not sure what the roadmap is.

You could certainly try it, but I think you will not be happy with the results, especially since the 3080 likely has more memory than the 1080 (though I don't know which versions you have).

You may have better luck in Progressive mode, though.

[Micha]

Against the LBS helps to use progressive mode. For non highres renderings it works quite good. Also for region renderings the progressive mode works much faster, since all GPU are used until the end. Only for very high resolutions the bucket mode is a must or the calculation will slow down.

[waldob]

Thank you Joelaff and Micha - I have a 1080 Ti 11Gig GTX and a RTX 3080 with 10 Gig. I thought the new RTX card will be faster then my 1080 Ti that is older?

Will try it with progressive mode . Thank you

[Joelaff]

The new card work be much faster, yes. Probably close to 3-5x faster depending on the task.