Problem with RAM

[JACKNIFE221]

I built my computer about a month ago and when i am starting hardcore games on steam, the ram usage flies to 100% and the game doesnt even run. The system just slows down then it freezes maybe a minute or two later. i just upgraded to 16 gigs of ram and put in a cooler master 750 watt power supply and a geforce 560ti overclocked. i have a core i7 2600k and a 2tb hard drive. i replaced a lot of parts and it still will not work. i can download the games but if i run any game that needs a lot of power it gives me a windowed blank screen and does'nt run. i have asked everywhere and there r no answers so far. Would appreciate any help.

[ShyguyXPC]

Updated DirectX to latest? Updated Video drivers to latest?

16GB is a waste for gaming, no games really use more than 3 or 4GB anyways.

What "Hardcore" games... few games on Steam are really "hard core" most will run fine on a mid range gaming system.

Windows Updates all updated? (Going to assume your running Windows 7 64-bit)