You could run X11 in 4Mb at one point, although I rather wished I didn't.

Yikes-- bringing back memories of frustration. X11 on my 486SX w/ 4MB was excruciating. It would swap like crazy. Adding 8MB more RAM made such a difference. Kernel compiles were much less swappy, too. (I can still the buy I bought the four 2MB 30-pin SIMMs secondhand from but I can't remember how much I gave for them in 1993 or 1994. I feel like it was more than $100, though...)