I have a pair of Gigabyte 5850 OC graphics cards, running in CrossFireX & had the dreaded 'screen flicker' problem that many others have!
After updating the CCC drivers to the latest & other so called solutions, I still had no joy.
I wanted to try 'flashing' both graphics cards to the same F12 VGA BIOS update, as they had different F11 BIOS versions... the easiest, safest & fastest way I found was by using GIGABYTE 'Easy Boost'.
<<< WARNING - As per any BIOS 'flash' update there are risks involved!! >>>
1. Download & install 'Easy Boost' - http://www.gigabyte.com/products/product-page.aspx?pid=3354#utility
2. Run 'Easy Boost'.
3. Click 'Live Update' & select 'Next (N)' to ensure you have latest version of 'Easy Boost'.
4. Click 'BIOS Setting' tab on left.
5. Select 'Model / Location' dropdown box for first GPU #1 - GV-R5850C-1GD (1,0,0)
6. Click 'Backup' & save VGA BIOS to your h/disc.
7. Click 'Autoflash' button on right.
8. Click 'Next (N)' button.
9. Select 'Region' - America
10. Select 'Bios Update Information' - F12 (there may be several options)
11. Click 'Next (N)' button.
12. Click 'Yes' when prompted to 'Flash bios now?' & wait until complete (Do NOT reboot after 'flashing GPU #1, wait until you have done both).
13. Repeat Steps 5 to 12 for GPU #2 - GV-R5850C-1GD (2,0,0)
14. Reboot System.