said by Freddy:
Did Red Alert 3: Uprising run smoothly before installing 8GB of RAM?
Also, it would be useful to know whether you're using a 32 bit or 64 bit operating system.
Yes, the system worked perfectly when I only had 4GB of RAM installed, on Windows 7 64-bit.
It turned out to be an BIOS issue, because ASUS originally made the U43 series to support a max RAM of only 4GB, but then later on decided that the chipset could support up to 8GB, and released a new BIOS to implement that change.