New m4400

Ddr2 are bloody expensive and eol, better off get a ssd and set up page file in case you run out of memory.
4gb is fine by today's standard.

 

Just an FYI - I am running a "refurbished" M4400 here...P8700 CPU and 4GB RAM. It has the factory-installed Win 7 Pro 32-bit OS. I didn't bother to install 64-bit OS, because I am only running 4GB.

I do a fair amount of graphics and some development work, not stressing the Nvidia graphics chip and so far 4GB RAM has been fine.

If your application needs MORE than 4GB RAM, then of course you will need to upgrade to a 64-bit OS to access it. That to me is the main reason to do it.

Some benchmark I've seen show that running a 64-bit OS with only 4GB RAM is actually SLOWER than running a 32-bit OS w/4GB, even when running those apps that have been compiled as 64-bit (which is possible with some CPU configurations).

The suggestion to upgrade to a fast SSD is valid, though, regardless of which OS you're running...either 32-bit or 64- bit, you will see a big difference in performance.