Whats up everyone, so basically have $300 max to spend on upgrading my system i built about two years ago.
MB: MSI 770-G45 AM3
CPU: Athlon II X3 2.7Ghz
RAM: OCZ Gold 2GB ddr3
Graphics Card: HIS Radeon 5770 HD 1GB 128 Bit
OS: Windows 7 Home premium 64 Bit
Power supply: OCZ 500W
Case: APEX Vortex 3620 Mid-tower
Going with the Phenom II X4 for my CPU upgrade and this RAM I found: Newegg.com - G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-8GBRL
But wondering since I still have about $180 to spend if I should try to pick up another Radeon 5770 and crossfire? But I'm guessing I'd need to pick up a 600W power unit if I wanted to do that? Also can you crossfire different brands of the same model graphics card? Since my current is an HIS 5770 but it was discontinued so Newegg only has a Visiontek 5770 now.
Anyways any advice or upgrade set ups would be much appreciated, thanks.