Ultrix 3.1 (aka UWS 2.1) memory requirements

[rusty at GARNET.BERKELEY.EDU]

According to the Software Product Description, for a VAXstation
II/GPX, Ultrix 3.1 now requires 6 MB of memory.  That's up 2 MB from
Ultrix 3.0.  This entry in the table has footnote number 9 next to it
and footnote 9 says "SPD memory specifications reflect the minimum
bootable memory configuration" so it sounds pretty grim.

Does anybody know if I can boot Ultrix 3.1 with 5 MB?  I know that
DECwindows eats up a lot of memory so I've been running vanilla X11
Release 3.