LOOKING FOR MOTHERBOARD WITH CROSSFIRE AND PCIEx1

[skidmarksteve]

Hi i just purchaced a Asus P5KC, because it suported crossfire and had a PCIEx1 slot for my terratec 2400i. However when using crossfire it disables the PCIEx1 slot, i have called the computer shop and they say that i am able to get a refund (as it was in the user manual and who reads user manuals before buying something?) , if i return it in 7 days. I also think that its a limitation of the P35 chipset. I was looking at the X38 chipset, more specifically the giga-byte GA-EX38-DS4

however it says:

1. 2 x PCI Express 2.0 x16 slots (The PCIE_16_1 slot supports x16; the PCIE_16_2 supports x16.)
2. 3 x PCI Express x1 slots (share with the PCIE_16_2 slot)
3. 2 x PCI slots

dose this mean i would have the same problem?
yes i found the answer, (Note 2) When the second PCI Express x16 slot (PCIE_16_2) is in use, the three PCI Express x1 slots become unavailable.

you may notice that the linked motherboard above was a P35 chipset, i managed to find a review of a Foxconn X38A. The important points was that its a x38 chipset board and the two PCIEx1 is disabled when the 3rd graphics card was inserted. This proves to me that the x38 can have crossfire and a PCIEx1 card at the same time. yay

now to decide between the P5E and the GA-EX38-DS4.

also i was wondering if anyone else has a x38 motherboard with crossfire and a PCIEx1 card running at the same time?

[skidmarksteve]

bump anyone confirm that this is possible?

[CraigMBecket]

Hi skidmarksteve,

Unfortunately some mobos only use one iRQ for all their PCI-e slots so when you use them in crosfire or sli mode the only slots that work are those used by the video cards. Similar problems can be found when you try and use multiple pci-e tuner cards, the board will accept one video card at x16 but only one additional tuner card in any pci-e slot, it certainly happend on an asus board I used.

Don't know a board that does what you want but suggest you start reading the manuals of various boards and look to see what IRQs are used by the PCI-e system.

Craig.

[skidmarksteve]

thanks, i did take back the asus P5KC and get the gigabyte GA-EX38-DS4, and everything is working now

I found some detailed block diagrams for the P35 and x38 that cleared everything up.

if you would like to know more about my upgrade i have put up a blog post about it.