Question about PciE x16 and crossfire

[Damn Dirty Ape]

So.. the IP35pro has 2 x16 slots, but one is noted as 'x4' even though they call it x16.. What does this mean to me if I wanted to crossfire or could I even?

 

[Sylvanas]

You COULD Crossfire on the P35 chipset (16x4 PCI-E 1.1) but it wouldn't be advisable IMO. The 2900's and 38xx series suffer at max a 20% performance hit by running in a 4x slot (generally 10-15%) and if you would want the new 4xxx cards that would probably be even more pronounced. Here is a recent comparison between 16x16 PCI-E 2.0 Crossfire and 8x8 PCI-E 2.0 Crossfire (note that 8x PCI-E 2.0 is the same bandwidth as 16x PCI-E 1.1). As you can see it's a pretty big impact between 16x16 and 8x8, and if you want to run a card in 4x PCI-E 1.1 then thats 1/4 of the performance of the P45 indicated in the review.

Bottom line it would probably be better to stick to single GPU in a P35 board and if you want Crossfire it would be better to get a new mobo.

 

[Damn Dirty Ape]

with 2 true 16x slots.... was just wondering how it would hinder the performance.. thanks

 

[ajaidevsingh]

I have done this with my 4850's and a asus P35 m/b there is not a huge drop in any game like crysis and bioshock!!