OTOY Forums

hello, I'm going to have a gtx 480 and a gtx 490. (both 1.5 Go per gpu)
which card do I must to use for display ? I want to use both for rendering.
Thanks.

Perhaps you mean a GTX590?
To use a card just as a display card you would set it to 'inactive' in the Octane preferences.
Because you want to run Octane on both cards both should be set to 'active'.
The display will be handled concurrently and consume some of the vram space available for Octane however as these cards are pretty good performers and all have 1.5gb it ought to be OK using both although it might stutter/delay some while it refreshes. Try it to see.
Probably Windows will pick the card in the first slot to use for the UI graphics.
You shouldn't have other programs open or run Aero or have a screensaver while you render in this scenario because it takes up valuable vram and what ever is left will be the amount each gpu can use for Octane, ie. if graphics is 512mb then all cards can only use 1gb since the same scene is loaded in each.
If you run into problems or need the full space it would be better to find a cheap basic single slot card for the display card (assuming you have a slot spare) and put in as well and then set that to be inactive while the other 2 are active.
Possibly you might decide to forego the use of the GTX480 and set it as your display card and use the GTX590 for rendering since 1024 cores by itself will be no slouch.
Probably this is the best compromise but as I said try it and see.
HTH

Thanks for your answer Now I'll try it and see
I'll try 580 for display (and for render I'll active it) and 590 (yes) always active.