Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
How much RAM does your PC have? If you run Windows XP, it is probably in the range of 512 MB to 1 GB. Older Windows versions will do the job with less than that, but as soon as you execute demanding applications or more than one application at a time, anything below 512 MB will likely translate into performance bottlenecks.
Of course, the more RAM you have, the better off you are - but how much memory do you really need?