Asus Asus P7P55D Intel P55 Crossfire Question

ndaar · 30 Nov 2009 at 16:15

Today i received my Overclocked I5 Bundle i ordered the other week when it was on special. The Motherboard is the asus P7P55D.I also got a ATI 5770 with it intending to add an other at christmas for crossfire.
I originaly thought that the board ran at 8x 8x as some reviews say, but there are other reviews that state it runs at 16x 4x.
I was hoping there was someone who had experience of the board and could confirm or deny it either way.
Also there seems to be mixed opinions as to the performance drop caused by going to 16x 4x ? Some state its 5% loss on the second card, others say the second card is useless.
Opinions? Reviews? before i bother to get an other 5770 to add to it?

Thanks

ndaar · 30 Nov 2009 at 23:50

no one?

Legion · 1 Dec 2009 at 07:00

The second slot is indeed 4x electrical therefore incapable of operating at 8x.

The good news however is that it is PCI-E 2.0 so that's equivalent to PCI-E 1.0 at 8x.
So it shouldnt be so much of a hit as you might first imagine.

Seeing as I cant find a review or comparison of the cheaper P55 boards using crossfire with the second slot at 4x,I can only link to this comparison of running a top end graphics card at different PCI-E speeds.

http://www.techpowerup.com/reviews/AMD/HD_5870_PCI-Express_Scaling/

If you really cant live with the loss of a few frames the cheapest Asus board to provide the full 8x/8x is the P7P55D PRO.

MeatLoaf · 1 Dec 2009 at 10:32

its definatly 16x4x, however theres a review floating round that shows that using a 5850 in a PCI-E 2.0 x4 slot only loses 4% performance comparted to a PCI-E 2.0 x16 slot.

ndaar · 1 Dec 2009 at 13:13

Yeah i saw the reviews and was encouraged, as i thought the loss would be so small. However i found an other review saying that infact it was less than 4x due to it been controlled by the south bridge and it throttling its bandwith down to 2.5?? Not sure how that affects things?

Maybe its better just keeping to a single GPU solution on this board, just never done crossfire or sli before and was looking forward to it. Maybe better off running a 5770 for a year then getting a 5870 next year when prices drop.