MicroVAX 3100/20 is apocalyptically slow even with 32MB of RAM

I have a MicroVAX 3100/20 with 32MB of RAM that once ran NetBSD many =
years ago. I recently had occasion to replace its disk and install 10.1, =
and it is superlatively slower than I remember it being. It=E2=80=99s so =
slow that it=E2=80=99s been trying to just bootstrap pkgsrc for about a =
week now, with pauses to allow the daily cron script to complete =
otherwise it won=E2=80=99t complete in less than 24 hours. The system =
time loses about 10-15 minutes a day, presumably because it can=E2=80=99t =
keep up with the clock interrupts. This is after I copied the GENERIC =
kernel config, stripped out all of the VAX models and devices that =
weren=E2=80=99t needed, and stripped out all of the RAM-based =
filesystems.

I don=E2=80=99t think RAM is the issue because I haven=E2=80=99t seen it =
go above 12-14MB active in top. It uses more swap than it does RAM.

Is there something configuration-wise I should try, or is this model =
just too slow to be supported anymore?