6850hd

hi....i would like to know if my current cabinet will be able to install amd radeon 6850hd or 7770hd? cabinet config is given at the end - my system config is ..... Intel(R) Core(TM)2 Duo CPU E7300 @ 2.66GHz Mainboard Model gigabyte G31M-S2 4gb ram ddr2 cabinet- iball mtstique Chipset...

I'm posting this thread on behalf of my friend. His budget is 55k + 5k for OS(win 7 home basic). Pls comment whether the following is ok or to make any changes. AMD Phenom II 955 BE @ 7.5k Gigabyte 880GM-USB3 @ 5.5k (whats the diff btwn usb3 and ud2-h version ?) Kingston 4GB DDR3...