I need some help choosing memory for my PC. I have an Asus A7N8X deluxe. If you're not familiar with it, it has Dual channel DDR 400 and up to PC3200. I want to get 512 mb memory. My problem is that the prices range from $56-$202. What makes the price vary so much? My intentions for my system are for graphic applications like Maya and 3D Studio Max.