I finally upgraded my Mac Mini to 2 GB of RAM yesterday. In retrospect, it was amazing that Leopard even booted up in the tiny 512 MB of memory that came with the Mini when I originally bought it a year ago. The 512 MB is even smaller due to the fact that 64 MB is shared with the video card. So an upgrade was definitely in order. However, the Mac Mini is notoriously difficult to open, due to the fact that there are no screws on the case (the cover is held in place by 16 plastic tabs). Fortunately, there is an absolutely fantastic tutorial from the guys at www.methodshop.com that covers upgrading both Power PC and Intel Mac Minis. Having followed the tutorial, I can say it was very accurate and useful. The only thing I would add is that in lieu of a magnetic screwdriver I used some Scotch Adhesive Putty to keep the screws on my non-magnetic screwdrivers.
While the Mini takes about as long to boot up as before, once it's up and running the performance difference is amazing. Before the 2 GB upgrade, one launched application would take up all the free memory and it was off to Virtual Memory swapping hell. Now I've got iTunes, FireFox, Xcode, and OpenOffice in four separate Spaces with plenty of memory to spare:
If your computer is chugging, do yourself a favor and get some more memory. My PC5400 DDR2 667Mhz SODIMM (2x1024MB) ran me about 60 bucks at Tiger Direct.com. It's the best investment you'll make in your computer.