Getting a new graphics card. Need some help.

[MDK]

So I ordered the Nvidia GTX 780 and I'm getting it either today or next monday. I currently have a GTX 590. My motherboard (X79A-GD65 (8D)) has 3 gen3 slots where 2 are 16x and one is 8x. I'm planing on using the GTX 780 as my primary card and have the 590 only for GPU rendering. I don't have alot of knowledge on hardware instalation since I try to avoid it. My guess is that I want to install the new card on the top most slot and the old one in the bottom one so they won't heat as easily. There are a few things I'm unsure about.

How much does it impact performance in octane if I put the old card to the 8x gen3 slot or even a gen2 slot?

How much does the old card heat up when I'm not doing GPU rendering and the card itself is not suppose to be doing anything at all? Do I put it in a PCI-E slot and only connect power to it?

Also any general information and tips would be much appriciated.

[kavorka]

the only difference on bus speed of the PCI slot in Octane is when loading your scene. Rendering takes a 0% hit on slower bus speeds. Also, the devs said the bus speed makes little difference even when loading scenes.

hope that helps you out.

[pixelrush]

Usually the main gpu will live in the first (top) slot because Windows assumes that however with recent boards you can often set the first slot order in the BIOS. Gigabyte mobo manuals usually have an entry for that. If you were trying to use sli there might be limitations as to where you can place cards ie first and second slots but I think you can do what you propose
When the 580 is not being used by Octane it will be idling and only 30°C or so and draw very little power. I don't think you need worry about turning it off.