Help with Crossfire performance

  hmsabry 14:20 01 Oct 2007

My computer is like this:
MB: Asus P5B Deluxe
CPU: Intel Quad Core Q6600
RAM: Super Telent DDR2 800MHz 2x1GB (4-4-3-8)
VC: 2 x Radeon 2600XT 512MB
PSU: Force 700wat
SC: Sound balster Audigy 2
OS: Vista Premium 32bit

When I installed the second video card, Vista rating for gaming performance remainded the same (5.4)
So I used FRAPS to measure the real performance of NFS Carbon & Lara Croft. I compared FPS for both Crossfire enabled/disabled (from Catalyst Control Center) and they are almost the same in term of FPS.
Based on these two notices (games performance & Vista rating) is there anything wrong/missing in roder to gain the performance boost of Crossfire?
I have tried all game settings from lowest to highest but every time I got the same FPS for enabled/disabled crossfire. Also I looked at the BIOS and pushed everything to boost dual GPU settings but no use. I don't know what's wrong...
By the way at 1200X1600 and AA & AF at maximum I am getting 12-15FPS for both enabled/disabled crossfire.

  citadel 19:10 01 Oct 2007

It may be the games you have tried are not optimised for dual cards. try a game that has been made to take advantage of two cards.

  hmsabry 19:33 01 Oct 2007

Thanks for your response I used Need For Speed Carbon and Lara Croft Tomb Raider Legend. Are not these games supporting Dual GPU?

My understanding is that GPU drivers (Catalyst Control Center) work seamlesly to provide the dual graphics power by enabling the Crossfire mode. In otherwords it is not dependent on the game.

  citadel 20:56 01 Oct 2007

need for speed carbon was faster with one card where fear, oblivion, and company of heros were faster with two cards, this was in tests in a vadim cetus with twin 2900xt's. custom pc mag.

  hmsabry 21:08 01 Oct 2007

Thanks. I will repeat my testing with these games.

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