Will I gain much in performance by upgrading RAM in my Dell Optiplex GX280 small desktop from 2 GB (2x 1GB DIMMs) to 3 GB (3x 1GB DIMMs)? I understand the 32-bit OS will not recognize >3GB so that's why I'm not shooting for 4GB (the physical maximum of this machine). The machne runs Win7 32-bit Home Premium OS and is rather slow. The alternative is to jump to a new machine, probably a i5 processor laptop (trying to delay that expense, if practical). Thanks much.
Just picked up an old optiplex myself, and found that though they are old they can still be efficient and powerful when pushed to better performance. Upgrade your CPU for around $20 to the Pentium 4 650 3.4ghz, this was a big step for me from the 2.8 ghz stock CPU. This CPU can also handle 64-bit processing, so you can max out the RAM to 4gb. Grab a Radeon Graphics card as well, I have the HD 4550 which is older but cheap and gets the job done with the stock power supply.
Old computers can still rock, especially for single threading and sever use!