ATI Crossfire HD4850 problem with X38

Hi all!

I am building a new PC ,here are the main features:
Motherboard Gigabyte EX38 DS5
Intel E8400 (3 GHz, not overclocked)
Memory-G. Skill PC8500 (g 4x1Gon but as XP32, I do recognize that 3 GB)
Food-Corsair TX650W
Graphics card: two Sapphire HD4850 connected in Crossfire with the two bridges (I have not forgotten the external power supply)Radiator-processor (it can serve) OCZ Vendetta 2

My problem is that when I run the test benchmark Crysis, I am at 32 fps with a card (when I say a card is not that I disabled the crossfire, but I have other outright withdrawn card) and when I activate the crossfire I am a 28 ....

I reinstalled the last Driver 8.11, but it is not moving Catalyst (incomprehensible), it does so that drivers can not activate the crossfire ....

So I tried to install the Catalyst 8.10, it works (with drivers huh 8.11) but still the same problem ....

With drivers on the original CD (Catalyst 8.4) always the same ....

I tried each card individually on each port PCI-E, with each cable feed, and everything is working correctly ....

I do research on the net, many assemble have this problem because of their chipset which bridles PCI slots, but as I have an X38 I'm not concerned theoretically ...

Thank you in advance for your help!

That may be a bit radical, but in cases like this, formatting, it works miracles and Resource as a lot of problems.

But if I remember correctly, there is not a specific meaning for the bridges ?

I think the X38 chipset is not ideal for the crossfire. Indeed when you put 1 single card, your PCI Express is 16X. When you put 2 ports pass 8X. Perhaps then just limitation. it seems a bit much as an explanation. You do have a other problem .

It is anything ....X38 = high end chipset = Full Speed CrossFire Configuration = x16-x16. There is more time P35 ....... Even the P45 are x8-x8 thus avoiding the bottleneck of data between the GPU.

Look no further, Crysis does not like the crossfire, moreover, have you tried on a game that works well in crossfire ?

Thank you for your answers ....

Just one thing, if I remember correctly, I had already succeeded Crysis 45fps with the same PC without changes ... but it wants more .... and tests appear to confirm what I say ...

The format, I think, but I also think all the games and to reinstall the backup has to go deep hidden folders .... therefore formatting ok but as a last resort ....
No other idea?
It can not come from a setting in bios?