Crossfire

You need identical cards to use in crossfire. If you use hem in crossfire the speed of the better card in this case in this case 6670 will be degraded to compare the speeds of 6550. Is that 6550 integrated graphics? If it is you cannot do that at all.
 
So you have an FX board with an A8 processor and 6550D onboard graphics and a HD 6670 dedicated card?

If so, you cannot crossfire those two. You would need one of two things:

1. An A10 chip which is compatible with and can be crossfired with the 6670
2. A HD 6570 which is compatible with and can be crossfired with your A8 processor

http://www.amd.com/us/products/technologies/dual-graphics/pages/dual-graphics.aspx#3
 


thanks a lot
 



thanks a lot