I don't know why you all think that it's RAM. Fully loaded X + KDE takes up a whopping 80MB of RAM according to TOP -- my resolution is at 1280x1024x32... Even with 128MB of ram in my system I have no problems using it. My swap space is at 1GB in size, if that makes much of a difference. I normally run my computer with a minimum of 256MB of ram in it anyways, as I tend to do some rather intensive stuff with it (Gaming for example).

Anyways, X will run fine on 64MB of ram, I know because I've got a P/233 w/64MB of SIMMs running X @ 800x600x16 and I've encountered no problems thus far. Granted, I'm using a prepackaged RH 7.1 installation of KDE, but I'm upgrading it to kde 2.2.2 in the next while, so I'll let you know if that's perhaps the problem.