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Hello, im going to buy a GTX 1080, i feel bad at selling my GTX 970, that GPU worked hard for me. <3
The Z-97P doesn't support SLI, but for Octane u need no SLI if i heard it right.

Can i work with 2 GPUs on this Mainboard? And if yes, is there a performance loss?
Sorry if my english is bad, thx for the help guys!

Hi,
You can do dual GPU, but the second slot is only x2 PCI lanes. So you would expect some performance loss :
- on first transfer before rendering
- Frame buffer on RAM (since V3)
- on OOC feature (Texture and geometry on V4)

I experience this with setting 1x, and also test with different PCIe Speed (x2, x4 and x8). No differenve on x8, slight loss on x4.
And I conclude that the network is better comparing between (2PC with 4GPUs (8x PCIe) is better than 1PC with 8GPUs (8x on 4GPU and x1 on 4GPUs), but need 2 licences !)

Thank you very much for the help!
Im pretty new to stuff like this, i would be happy if u can answer me some more questions.
- Is the performance loss high? It should only affect the GTX 970 if i think right?
I have 3 options:
- Sell the GTX 970 and only use the 1080.
- Buy a new psu and use the 1080 with the GTX 970.
- Buy also a new Mainboard, so i would have no performance loss. (But is that really a good idea, to spend another ~80€ for a mainboard, just for the new slots?)

Thank you very much!

Hi,
- I don't remember exactly, but it's about 6 to 10%, depending of the scene on 2x PCIe (your second slot). The performance loss will not affect the rendering process, but only transfer from VRAM to RAM. So, I cannot say for the 970, I have test this with titan1.
- You can keep the 970, it could help the rendering. Each card will render at its speed. But I remember that on one of my test with 4 titans (3 on 8x and with one on the 1x), and the performance is not so significant than 3 titans only on 8x, but it depends on the scene.
- option 2 and 3 still need a new PSU.
- and also, the 970 has only 4GB, so if use with 1080, you're limited to only 4GB.

Thank you very much for the help!
I hope the impact from the crappy GTX 970 Vram is not too big, but i think i keep it.