im thinking of crossfiring my pc. i'm currently using a MSI HD radeon 7970 and Asus Sabertooth z77 and how can i tell what graphic card is going to work with my MSI 7970? im thinking of getting another MSI 7970 but they are quite rate here, so incase i cant find one, i'm going to get another card to pair with my msi 7970 but i dont know which one to get
The MSI R7970 is a "reference card", basically the same as any other branded reference card. Things you want to check is the specs of the 2nd card. If the clock speeds or memory are higher than your MSI the 2nd card will "down clock" to match you card.
Basically, any other 7970 will work.
What other brands are available at your local / online shops?
Adding the 2nd card is as simple as installing the 2nd card in the 2nd PCIx slot and using one of the Cross-fire cables to link the two cards. Then in Windows, open the AMD Catalyst center and enable Crossfire in the left-hand side menu.