I have a pretty old computer (about 6 years) but I've recently updated a few components such as ram and video card. I had 2GB of ram and now I have 6GB (all compatible) but I don't notice any difference. I had a GeForce 8800 and now I have a Radeon 6850. I'm doing some rendering but when I look at the task manager its saying my CPU is being used 100% and only 1.81GB of ram are being used. I don't think this is what's supposed to be happening. How can I fix this?