I got bored and wanted to see what would happen if I put my 5850 from my other computer into my 5870 rig for x8/x8 crossfire.
So, now I have a rig running x8/x8 Crossfire with 5870+5850. I have one crossfire bridge installed, the power is plugged in for sure, and I am running 11.2 drivers, but my framerate is lower in every game I have played compared to my single 5870 running in x16. Crysis was getting 37fps average at 1920x1080 with single 5870, and now I get 35 or lower with Hybrid CF.
I have read benchmarks comparing x8 to x16 bandwidth. Supposedly there shouldn't be an issue running these cards in crossfire in only x8/x8.
Any suggestions? Thanks
Gigabyte GPA890 AM3 motherboard
AMD Phenom x4 965 @3.9ghz 1.475v 125w (C3)
Gigabyte Radeon 5870 + Gigabyte 5850
Corsair 1333mhz ram X8GB
Corsair TX750w PSU
Coolermaster 690 II Basic Case
Noctua NH-D14 Cooler
D-link Extreme Wireless N PCI
Asus DVD/CD drive
2xBarracuda 7200rpm 500GB HDD
Windows 7 64-bit
Try tweaking the CF profiles with Radeon pro( http://www.radeonpro.info/en-US/ )
For example, select BC2.And in the CFX settings,select Alternate Frame Rendering(For MVPU mode) and AFR-Friendly D3D(for "Force CrossfireX profiles") and see if your FPS improves or not