Performance gain running 2 asus gtx 780 direct cuii oc

[Tester1986]

Hello all,

to cut a long story short my old corsair cx600 psu has given up on me so i now need to buy a new one as i have this unfortunate oppertunity i quite like the thought of running 2x asus gtx 780 direct cuii oc gpu,s however i only have 1x16 pcie slot on my mobo and the other is x8 now from doing some research i see that my cpu can only handle 16 threads anyway so what will be the differnce if any useing 2 gpu's on a x8 basis?

Current Rig

MOBO:Asus P8Z77-V LX

CPU:i5 3570k @ 4.7GHZ
Cooler:Corsair H80i (2013 eddition)
RAM:16gb corsair vengenance 1600mhz
GPU:Asus GTX 780 direct cuii OC + OCED 20%
SSD:Samsung 840 pro 128GB
HDD:Western digital caviar black 1TB
Case:Aerocool X warrior with additional 4x120mm LED Fans
PSU: To Be decided - RIP CX600

Thanks in advance

 

[Shmee]

running at x8 speeds should be fine, as long as they are PCIE 3.0, and even then PCIE 2.0 would probably not be much of a bottleneck. Just make sure you get a good enough PSU for SLI, you probably would need a lot more than another 600W PSU for 780 SLI, especially with OC.

 

[KaRLiToS]

running at x8 speeds should be fine, as long as they are PCIE 3.0, and even then PCIE 2.0 would probably not be much of a bottleneck. Just make sure you get a good enough PSU for SLI, you probably would need a lot more than another 600W PSU for 780 SLI, especially with OC.

^^ I agree with you.

You won't see much difference between PCIe 2.0 and PCie 3.0.

And for GTX 780 SLI, I recommend at least a good quality 850w PSU if you are not going to overclock.

https://www.youtube.com/watch?v=qrNfZkZYCjs

Check this out, between PCIe 2.0 and PCIe 3.0 there is a max difference of 7.5% according to the vid.

 

[Tester1986]

After looking if my mobo was pcie 3.0 and it is! I found a snag i do not think i can get around or can I ?? my mobo only supports crossfire but not SLI

do i also need a new mobo or is there a way around it?

Thanks for the response so far

 

[KaRLiToS]

edit.

 

[notty22]

That m/b does not support SLI
http://www.newegg.com/Product/Produc...82E16813131824
It does not do 8x 8x.
Its specs a 16x top pci-e and bottom 4x from chipset.
It does not have the micro-switch to split lanes to another pci-e .
m/b makers do this for market segmentation.

 

[Tester1986]

That m/b does not support SLI
http://www.newegg.com/Product/Produc...82E16813131824
It does not do 8x 8x.
Its specs a 16x top pci-e and bottom 4x from chipset.
It does not have the micro-switch to split lanes to another pci-e .
m/b makers do this for market segmentation.

So i would need a new mobo SHXT,mobo sugestion?

 

[Shmee]

It is going to be a bit hard to find a better Z77 board, especially new. Now if you want, you could upgrade to the Z97 platform, but this of course would require a new CPU. Unless you really want to upgrade the whole platform, I would recommend just using a single 780, or possibly selling it and going 290 crossfire, that is if it will run on the board :/

 

[Reaper_Tech]

PCIe 2.0 should not be an issue for SLI in x8 x8 but since your board is x16 x4 and only supports Xfire you need a new board or just stick to single GPU and hold out till you upgrade again.

That said any Z77 board with sli support should prove good enough most of the boards perform similarly its the BIOS and its options that really differs .