1155 Board PCIE3 handling for dual GPU

[Hennerst3]

Hey guys
Sorry if this has been answered in another thread - but I searched & could not find, correct me on it if it's been done

for the 1155 boards & Pcie3
When using dual GPU, some of the boards can only do x8/x8. Is this still running x8 Pcie3 speed, or downsample to x8 Pcie2 speed?
Example board ASRock Z77 Extreme6
http://www.pccasegear.com/index.php?main_page=product_info&cPath=138_1183&products_id=19870

I know that with the better chip addons, there can be dual x16 as like with this one
ASUS P8Z77 WS
http://www.pccasegear.com/index.php?main_page=product_info&cPath=138_1183&products_id=20070

I've tried research on it but I just can't seem to find the answers to my question. I'm looking at upgraded from 775 to 1155, but don't want to run into the trap of getting x8/x8 pcie2 speeds on 1155. I've got a gtx 670 & planning to get another

Cheers
~Hen

 

[ozan]

Hi Hen,

According to HARDOCP's tests, you will get about a %7 percent increase in framerates from pcie Z68 vs Z77.

These boards are both Z77. I don's see the P8Z77 WS giving you any real life advantage.

 

[EarthDog]

This shows a lot different... : http://www.techpowerup.com/reviews/Intel/Ivy_Bridge_PCI-Express_Scaling/23.html

 

[Hennerst3]

Hey guys, thanks for the responses, really helped

But I finally found my answers here
http://www.anandtech.com/show/5458/the-radeon-hd-7970-reprise-pcie-bandwidth-overclocking-and-msaa
http://www.overclock.net/t/1329226/building-a-new-computer-which-cpu-intel-i5-3570k-or-amd-fx8350/30
Some of the boards revert to pcie2 x8/x8 when in sli/xfire

You can close this thread

 

[EarthDog]

Never heard of them going back to pcie 2. Just 8x/8x pcie 3 which us equal to pcie 2 16x/16x....

 

[TerranBrackiatt]

The only reason it would revert to pcie 2.0, is if one of the 3 components was 2.o. z77 is 3.0. Gtx 670 is 3.0. So as long as the cpu is also 3.0, you're good to go. IE sandy or ivy bridge. Earlier than that will still be 2.0 and slow the whole system down.