fvwm was always faster than TWM, even if at a first TWM runs faster. Also, TCL would be faster than Java :)
But mostly I was just shocked anyone could think running a wm could reasonablyrrequire a gig of ram...
Eh, most people run Fvwm/Blackbox/WMaker with 16MB/32MB of RAM. 8... well. To be confortable enough, maybe with NetBSD, FVWM, URxvt, a ultraslimmed kernel and jikes/any tiny Java compatible VM.