Open the windows task manager and watch what is maxing out all the time when the system slows down. Do you run out of physical memory? Or is it the processor that is pegged at 100% performing some operations. Normally its a ram issue for me, and I only run a PIII 1.0 GHz, with 756 MB ram.
I use GIMP for my image processing mainly now, and sometimes still Corel Photopaint. In either case as soon as I run out of ram and it starts using the virtual ram (hard drive swap space), the system starts bogging. Even with only 1.0 GHz, that really doesn't affect me too much unless I am running some complex operations.
