It looks like something else is causing problems on his machine. I seriously doubt that it has anything to do with eclipse. Maybe there are some security settings preventing the automatic updates. Perhaps the OP has some Cisco agent running in the background taking up CPU and memory.

I am with Deliverance. Currently I have two eclipse projects open, one is taking up 214MB of ram, the other 92MB. I have firefox open with about 40 tabs and that is taking up 395 MB of memory. CPU utilization is < 25% and I have 2.44GB of memory free (4GB total).

I agree that eclipse is a bit of a memory hog, but not to the point that the OP is describing here. I would suggest deleting eclipse, redownload it and try again.