Some programs have additional features too. Like Crysis won't let you use the level editor unless you are using a 64 bit OS.
That's true, but you'll find that some programs seem to run smoother - at least the ones that support it. I'm not saying Dolphin is a program for average users, but for example, it does take benefit from the x64 architecture. But 4GB is slowly getting the standard for PCs, so you might want to go with x64 from here. I have 6GB myself, and it runs much smoother than when I had 3GB. I'm using the 1366 platform, so that's triple-channel memory. I went with 6x1GB.
I don't really care for PC-games, but I've read that, too. You're just a step ahead by having x64. Most programs are updated to work with x64, even though they may not really beneift from it.
Your CPU is a single core comparable to Intel's atom. It should have been 64-bit compatible because anything more recent than an athlon 64 is, which your's is. I believe the least cost effective way to upgrade would be just new cpu and mobo and reuse your RAM if you are only using it for class work.
easiest way to check if you CAN run x64 is open regedit, go to HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\Cen tralProcessor\0, ProcessorNameString will give you the name of the CPU and Identifier will tell you which family it belongs to, if it says something like Intel64 Family 6 Model 23 Stepping 10 then its 64bit capable.
The only downsides to x64 is that if you have any old hardware that required proprietry drivers, your probably not going to get them running. Same with really old (16 bit) applications.
Core stepping G2
Manufacturing process 0.065 micron SOI
Data width 64 bit
Number of cores 1
Floating Point Unit Integrated
Level 1 cache size 64 KB 2-way associative instruction cache
64 KB 2-way associative data cache
Level 2 cache size 512 KB exclusive 16-way associative cache
Physical memory 1 TB
Virtual memory (TB) 256
AMD 64 technology
Enhanced Virus Protection
Low power features
Stop Grant state
Dual-channel DDR2 SDRAM memory controller
Is that the specs for my cpu?