Gigabyte GA-Z68MA-D2H-B3: graphics card in PCIe x4 slot

[max789]

Hi

I'm trying to understand how graphics card performance will be affected using different PCIe x16 slots in a Gigabyte GA-Z68MA-D2H-B3.

http://www.gigabyte.com/products/product-page.aspx?pid=3855#ov

This mobo has three PCIe x16 slots, with one wired as x4, which is linked to the Z68 chipset. The other two are connected directly to the CPU (both at x8 if two graphics cards are inserted).

Is it true that, by design, a display card in a PCIe x16 slot linked to a CPU directly will be able to utilize higher bandwidth, compared to one in a slot connected to the Z68 chipset?

Imagine the following scenario: three PCIe x16 graphics card are inserted in the above three slots. No games or 3D programs will be run, ie, low bandwidth requirements. Will there be any real performance difference amongst the three?

Your feedback and insight, please!

 

[plugwash]

This mobo has three PCIe x16 slots, with one wired as x4, which is linked to the Z68 chipset. The other two are connected directly to the CPU (both at x8 if two graphics cards are inserted).

Is it true that, by design, a display card in a PCIe x16 slot linked to a CPU directly will be able to utilize higher bandwidth, compared to one in a slot connected to the Z68 chipset?

Yes that is true but the situation on P67 (and presumably Z68) is a lot better than it was on P55. Using a NF200 for a three way crossfire setup still beats using the PCH but not by much.

http://www.tomshardware.com/reviews/p67-gaming-3-way-sli-three-card-crossfire,2910-16.html

Imagine the following scenario: three PCIe x16 graphics card are inserted in the above three slots. No games or 3D programs will be run, ie, low bandwidth requirements. Will there be any real performance difference amongst the three?

I very much doubt there would be any measurable performance issues in such a situation.