[java] Low Lag IDE

JCreator seems to be quite popular (mostly because of it's speed). But I've heard the latest version got slow and buggy, so you might want to try an older version.

jEdit.

Also removing spyware, and unnecessary things from tray, helps too.
Are you using Eclipse with reasonable switches? Like - server, or -Xmx500M?
I don't recall if they are used by default.

Dunno, if he's running Windows that amount of RAM is probably the killer. I'm running eclipse right now on WinXP with TWO GIGS of ram and it looks like it's only using about 110mb (heh), but Eclipse is still getting WAY more page faults compared to everything else I'm running. (Even blowing away explorer.exe, thanks Windoze..)

If that's it's true requirements, add onto that Windoze, and add onto that your own development requirements--with less than half a gig of ram I'm going to wager that you're screwed. :D

I heard GEL (I have the name right?) is a very small download and if that's the case maybe it won't hog memory so much.

Thanks for all the suggestions, I will try all 3 and decide which one I prefer.

I'm buying a new computer within the next 3 months, I think I'm going to use Mandrake Linux despite how much I wanted to play Neverwinter Nights.

If you going to use Linux, then you can't use GEL and JCreator I believe, don't know about jEdit.
For fast and rich features IDE I still recommend GEL over than JCreator.

JEdit is *not* an IDE. Seriously, people, don't say it is. It's called JEdit for a reason. It's an editor. Yes, it has some plugins that greatly expand its abilities, but please don't make it out to be more than it is.

That said, JEdit is a wondeful text editor. Arguably my favorite.

Out of curiosity, what speed CPU do you have? I don't usually have any lag issues using Eclipse, but then again, my computer is fairly fast (Athlon XP 3000+, 512 MB RAM). On Windows, JCreator is not bad, and since there's a free version, that's also definitely a plus. I still like Eclipse better, but if you're having issues with it, then JCreator is good enough and is quite light on the resources.

I'm using it as an IDE. It works as nice as Eclipse, without an autocomplete and some other Eclipse's features. I like moving source files by hand, so jEdit works in this case better than Eclipse.
Eclipse worked well with 450 MHz Celeron with 220 MB RAM. FSB clocked on 85 or so.

Re TomX

You could use Linux and windoze as a dual boot. First install windoze, then Linux and setup LILO.