Originally Posted by David Wright
32 bit games like Race On (and most other games) are limited to 2GB of operating system memory, even in a 64 bit OS.
Yes, the only benefit to having all that RAM and
a 64-bit OS is that each application gets it's own 2GB address space (not including video RAM as with 32-bit OS) and you still have plenty of memory left for system processes.
The 4GB limit in a 32-bit OS includes video RAM in the equation.
32-bit OS with 4GB RAM and 2GB video RAM (SLI) = only 2GB available system RAM.
64-bit OS with 4GB RAM and 2GB video RAM (SLI) = all 4GB still available for the system.
So even if your games are 32-bit, you do get a nice amount of extra headroom by having a 64-bit OS with 4GB or more of RAM.