Rampage III Extreme with dual GPU Crossfire + extra PCI-E Raid, howto config?

[Retired]

Hi.

I have two ATI displaycards (PCI-E, slot1 & 3) in crossfire, and one extra PCI-E Raid (PCI-E, slot4). After assemble and installation I notice that slot3 is downgraded to PCI-E x8?

How to assemble/configurate the system? When I need 2x PCI-Ex16 for the displaycards and 1x PCI-Ex8 for the RAID card.

[TrickMasterPC]

Are you using the Rampage III Black Edition?

Check your motherboard manual for the PCB diagram which indicates which slots are 16x. The Raid card cannot be seated in the same PCIe bus channel as the Graphics Cards otherwise it will default the speed of at least one of your cards to 8x (sharing the bandwidth).

You can seat that RAID card in any PCIe slot 1x all the way to 16x (no problem). The card if seated in an x16 slot will still only function at 1x speed. Although, a 1x RAID card will give you much worse RAID performance than the onboard Intel SATA II Controller. I would not even recommend running a 1x RAID card. You should go with 2x or 4x in order to achieve solid Read/Write speeds.

If you still want to use that 1x card mount it in a lower PCIe slot. Boot and check your Bus Speeds. If still at 8x on one of the graphics cards move it to another PCIe slot and try again.

[Retired]

Hi, thanks. Everyday I learn something new. PCI-E has maximum of 32-lanes so there is no way to get full performace from my displaycards.

My Raid is "HP lsi megaraid sas 9260-8i" and I need PCI-E2 8-lanes (equals 4000MB/s) for it, to receive full performance of my SSD drives. So next question is should I put both my displaycards in PCI-E2 x8? Or can I get better performance if I put one in PCI-E2 x16 and other one in PCI-E2 x8 (And how about stability)?

And my motherboard was "Asus Rampage III Extreme". And motherboard has one PCI-E1 x4 (equals 1000MB/s) so I can't use it for 8xSSD (550MB/s per SSD, total theoretic speed 4400MB/s)

[TrickMasterPC]

If you game a lot, then you definitely want your graphics cards to each run at the full x16. You should be able to slot your RAID card in one of the lower x16 slots and it should default that slot to x8. That was my experience running 3 way SLI. Two cards at x16 and one at x8. Should work the same way regardless of the 3 card installed.