I have an HP Pavillion Elite e9300 computer, AMD X4 820 quad core, 6GB DDR3 SDRAM, 1GB ATI Radeon HD 5450 -monitor ViewSonic VA2226-11 Model #VS11803 at 1680x1050. I have recently upgraded my psu to a LSP “professional” 750 watt. I am shopping for a new graphics card for under $150. I do online gaming , light video editing etc. The Radeon HD 5770 has been recommended. When shopping I see various manufacturers - Diamond, XFX, Sapphire, Sapphire Vapour.... Also there is an XFX single slot HD 5770. Prices range from $120 - $250 for the same card? Single slot is cheaper ( I assume not as good). I’m not savvy enough to go by the specs. I have looked at sites like hardware compare but they don’t list the different manufacturers. So a) how do I choose? Just by price? And b) is there any reason I should stick with Radeon instead of say NIVIDA is the a better choice than ATI?