Advice please?

[jeff213]

Hey everyone. Not too long ago i purchased 2 ATI 4850 cards to upgrade the performance of my pc. To test that the cards were working to a sufficient standard , i used the game Crysis to test them. Firstly i enabled Crossfire X on my system, enabling both of them to work together yet i found quite a few problems with the setup. The game took forever to start and in the unlikely event that it did, it did not perform well at all - couldn't even run all settings on high without AA. Curious of this strange problem i troubleshooted many times yet to no avail. When i disabled the Crossfire setup, and instead only ran 1 GPU i was astounded because it run brilliantly on all "Very High" settings, full AA perfectly. What i don't seem to understand is how the hell the Crossfire setup running 2 GPU's could not perform properly, yet a single one could.

My system information as is follows:

Intel Core 2 Duo CPU E6750 2.67 GHZ
4g DDR2 memory
2 X Sapphire HD 4850 ATI cards 512mb ram
Windows Vista 32bit
500gig hard drive
GA-P35-DS3P motherboard

Please offer advice to how i could get my Crossfire setup running properly or tell me whats wrong with my configuration. I personally believe that the problem lies within the motherboard i am using, a P-35 chipset has 2 PCI Express X16 slots, but when running a second GPU, the second one only runs on X4. I think that because of that it brings the other one down, hence slowing it down massively.

[martini161]

what kind of powersupply do you have?

[DMB2000uk]

Asides from having lack of power as being a possible cause, you've probably already identified the main cause of your problems, the lousy x4 connector on the second PCIe.

Are you at the latest BIOS for the motherboard?

What version of the ATI drivers are you running?

Do you have any other games to test crossfire performance?

Try running 3DMark06 and see what numbers you get in both crossfire and single card modes.

Dan

[jeff213]

I'm running a 750 Watt power supply that has the capability for 2 cards. I'm pretty sure that its not the problem though. It probably is the P35 mobo. Btw can someone plz explain BIOS to me. I'm sure i've got all the updated drivers for everything.

[martini161]

BIOS: basic input output system. what do you need to know about it?

[Sparky]

Basic Input Output System. Your mobo's manufacturer may have an updated BIOS on their website under downloads and support perhaps. BIOS can be accessed by pushing either "delete" or F2 prior to the OS loading. Some boards show the BIOS version prior to boot, if that's not the case you can boot in to BIOS to look for your version or you can run CPUZ and click on the Mainboard tab to view which version you have loaded.

[vbironchef]

I have been reading that you need to set the game for crossfire mode or something like that. Has something to do with the right drivers for crossfire.