Crossfire not fully functioning?

hello, this pc has q8200 stock, 2x 4850 512mb, mis p45 neo2, and OCZ 600w, 4GB ddr2 800
im having hard time setting up this crossfire. i enabled crossfirex in ccc, but GPUZ says it is disabled.
i ran 3dmark with one card and i got 11825, with two card 13573.
SM2 increases 300 when i hav two cards, SM3 increases 800.
this seems not normal.
i enabled the crossfirex logo to appear in right top corner when running 3D apps.
when i run GTA4, and go to graphics options, it says i only hav 512mb available. and the crossfire logo is showing.
no difference between one card and two card.

also i used riva tuner to see how much gpu is working. whenever i run 3d apps, both gpu usage wont go over 50%.

one game i found out to be working with crossfire is GRID, both cards go up to 90-100%, and i get more frames.
please help me with this solution
7 answers Last reply
More about crossfire fully functioning
  1. Crossfire does not work in all games. Only games optimized to do so will show benefits. I do not know if GTA4 is one of these or not (look up some benchmarks to see if reviewers got improvements).

    Crossfire does not double ram. 2 512 MB cards should show 512 MB.

    On some OSes, especially 64 bit ones, I know GPU-Z has issues detecting Crossfire.

    A q8200 will limit you a bit in older games that are not multithreading since its clock speed is somewhat slow. In the cases where Crossfire seems not to do much but is supported in the game, this may be the case.

    To help clear up any other problems, you could try reinstalling the drivers or trying older/newer ones. And if all else fails, a full reformat never hurts.
  2. thanks for reply
    i did reinstall drivers few times. and what about 3dmark?? only 2000 difference?
    im sure its not cpu bottlenecking two 4850s, its never at 100% usage during games, not even one core, 4850s are not like 5850 or 5870, or gtx295, 285s.

    im using xp
  3. Yeah, my only experience with dual cards were my 6800GTs, and they doubled my 3DMark05 score (from 1 6800GT). I guess from here, just go back and double check that all plugs and both bridges are snugly attached. Then, double check that Catalyst thinks it is in crossfire, and then also make sure Catalyst AI is set to advanced. Also for testing purposes, turn VSync off.
  4. yeah,, no change, i redid everything, thanks for help though
    no other way to findout what is going on with this??
  5. If the xfire symbol is showing up then it is working. It sounds like Grid is confirming it too.

    What 3D apps in particular seem to not be using xfire? Just GTA?

    Are your 3D settings in CCC all set to high settings? I was playing around with the AA through CCC for example and it doesn't work at all IMO yet it causes a performance hit. I would go through them and make sure they are all letting the application choose. It could be an explanation for the small increase.
  6. they are all at app choose. , i havent tried other games yet but, my wonder is why 3dmark06 has only 2000 increase over another card.
  7. you will have to overclock ur cpu to about 3.5 both cards should work @ 100% then and your 3d mark will be higher
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