Sorry for the broken English!
MSI Radeon HD 7770 - R7770-2PMD1GD5/OC
Asus Radeon HD7770 - HD7770-DC-1GD5-V2
AMD Catalyst Driver Version- 12.8. Also tried all drivers launched in the past 2 months
Operating System: Windows 7 64-bit Ultimate
Issue Details: Every time I want to enable or disable Crossfire X from the Catalyst Control Center the system freezes and a hard reset is the only option. I can only enable or disable Crossfire X if I perform a clean install of the AMD driver. After the fresh install I can enable or disable Crossfire only once. After this any other attempt to enable or disable it results in system freeze and hard reset is required. The system runs fine with either of the cards installed and I have tested both of them for overheating or other issues and I have not been able to find any problems. It does not matter which card is installed in which PCI-E slot, the problem is the same. The cards are not and have never been overclocked.
Another problem is that while Crossfire X is enabled DOTA 2 will not work. The game freezes after about 10 minutes of gameplay. This is not such a big problem since it runs perfectly with only one card but not beeing able to enable or disable Crossfire stops me from playing the game without performing a clean driver install.
Another issue is that while Crossfire is enbaled, Firefox becomes unusable after 1-2 minuted of browsing. The screen turns black or becomes heavely pixelated but only in the Firefox window, the rest of the system functions correctly. Closing and reopening Firefox solves the problem but only for a few minutes. This issue has made istelf aparent in several versions of Firefox I have tried. It would not bee a problem if I could enable Crossfire only while I playh certain high demanding games.
Motherboard: AsRock Z77 Extreme4
CPU: Intel Core i5 3570K @ 4.2 Ghz, 1.240V, x42 multiplier
RAM: G.Skill RipjawsX 4GB DDR3-2133mhz 9-11-9-28
PUS: Corsair HX-750W
Display Devices: Samsung Syncmaster 2243NW connected using a VGA cable
Motherboard Bios: AsRock 2.20
No other PCI-E or PCI cards are currently installed.
The system has been tested for Overclock stability with Prime 95 and Intel XTU and has passed 8 hour long stress test.
Both GPUs have been tested on a Uniger Heaven 3.0 loop, and both have passed without any problems both individually and with Crossfire Enabled. No problems are aparent in high-demanding games ( Crysis 2, Metro 2033, Skyrim) while Crossfire is enabled. Performance in these games and in the benchmark is more that satisfactory while Crossfire is enabled. Temperatures for both CPU and GPu have been well into acceptable parameters. No blue-screens or system freezes have happened during the stress tests.
I hope there is a solution for my inability to turn Crosfire On or Off. I am currently using only one card because of these problems.