Those are some of the larger more resource hungry programs available.
Throw in a few more like OpenOffice and you might just be able to grind you machine to an incredibly slow speed so that it is unusable. I’ve older hardware so perhaps I’m more sensative but Gnome is definately far far slower than Windows 2000.

You might also try running gimp –no-data
Gimp is simply not designed to be slim or fast by default, even if you were a proffessional user and kept it open all day it would be difficult to make use of it all the features even if you were trying, so I’ve never though it was the best strategy and I wish they’d just load things on demand as and when they are needed.

You propably knew this already but you could check your /proc/sys/vm value. Bigger the value is, more actively Linux swaps.