Difference between 2xPCI-E: 8x8 vs 16x16

[walt526]

I'm trying to select the motherboard for a new build and I've never had a dual GPU system before. Is there a huge performance difference between having both cards at x16 versus both at x8? Most of the motherboards that I've come across that just have (2) PCI-E x16 slots run both cards at x8; the only ones that I've found that support (2) x16 cards simultaneous are ones that have (4) x16 slots (both those all run at x8 with 4 GPU's).

I'm definitely not interested in (4) GPU's, just (2). Is it worth the ~$60 for a more expensive motherboard that can support 2 GPUs at x16?

Lastly, so far I've been looking just at ASUS and Gigabyte so far, but if there are good manufacturers that offer dual x16 (not 2 @ x8) then I'd consider them.

Thanks.

 

[badge]

I'm trying to select the motherboard for a new build and I've never had a dual GPU system before. Is there a huge performance difference between having both cards at x16 versus both at x8? Most of the motherboards that I've come across that just have (2) PCI-E x16 slots run both cards at x8; the only ones that I've found that support (2) x16 cards simultaneous are ones that have (4) x16 slots (both those all run at x8 with 4 GPU's).

I'm definitely not interested in (4) GPU's, just (2). Is it worth the ~$60 for a more expensive motherboard that can support 2 GPUs at x16?

Lastly, so far I've been looking just at ASUS and Gigabyte so far, but if there are good manufacturers that offer dual x16 (not 2 @ x8) then I'd consider them.

Thanks.

Sticky at the top of Graphics Forum.

 

[walt526]

Thanks, I actually read the sticky but it didn't really answer my question: is the performance improvement worth the ~$60 to get a more expensive motherboard that supports dual x16?

 

[badge]

Depends on what video cards you will be using and what games. There is a lot of benchmark data out there comparing the two setups. Generally, the bandwith of an 8 x 8 setup is more than enough, but not in all instances.

 

[boulard83]

8x ~ 80gbs
16x ~ 160gbs

As badge told. 8x8x can do it. Lots of bench show that its currently GPU/platform bottlenecked and not PCIe lane bottlenecked.

For the best SLI/CF performance i suggest I7. They scale really better with multi GPU.

 

[badge]

From the Sticky linked:


...Dual 8x is a very good configuration too,it doesnt have alot of difference with Dual 16x and its cheaper too...

http://www.tomshardware.com/reviews/crossfire-pci-express,2095.html

 

[baddad]

These manufactures ASUS, EVGA, Gigabyte, MSI, XFX, are the ones you should look at.

This board is a great buy now and it has 3 16x slots http://www.newegg.com/Product/Product.aspx?Item=N82E16813131274