Hi, I tried running Left 4 Dead with the following key components: Intel E6300 @ 2.8GHZ Kingston 2gb DDR2 667mhz Geforce 8400GS 512MB 450mhz Cooler Master 500WATTS PS However, I have very unstable frame rates (yes I have installed the latest drivers for my mobo and the gpu) even when I choose the video settings to very low. I have tried running on Can You Run It? and it passed the recommended requirements easily. I have tried the game on my previous computer with the following key components: Intel E8400 @ 3.0GHZ Kingston 2gb DDR2 667mhz Geforce 8800GT 512MB 640mhz Antec Earthwatts 500WATTS With the above parts, I could run the game smoothly even at the highest settings. The only difference I see in these 2 computers are the GPU and the processor in which the first com isn't very far behind...so pros, please help me on this! Thanks.