Hi, this is my first time posting here, so please excuse me if I did something wrong. I've "inherited" a PC with the following specs: AMD Phenom(tm) II X4 945 Processor 2x 2GB Corsair CMX4GX3M2A1600C9 RAM M4A785TD-V EVO motherboard SAPPHIRE ATI Radeon HD 5770 450W PSU <- random brand I would like to invest in a new graphics card. Xfire is not an option because the mobo's second PCIE slot is only 4x. Obviously, I want to play games with some eye-candy at 1920x1080. So far, whenever I do switch on AA and AF, or even go 1920x1080, the 5770 is lagging. So, the question is, should I bite the bullet and fork out for the PSU and GPU or is something obviously wrong with this setup?