I'm about to upgrade my home box to a SparcStation 20,
You mean the model before the Ultra 1? I guess I am not the only one with his own museum ;-)
which should run Self a bit more nimbly than the SS5 I've got now (although I'm amazed at how well Self does run on the 5).
With enough memory it is reasonably usable.
The question is, would Self benefit particularly from multiple processors being fitted to the SS20? Any notions?
I used a Meiko with 10 SS20 processors for a while and since I was sharing it with other people this made a noticable difference. Self doesn't use "native threads", but if you run the X server on the same box then multiprocessing might help even if you are the only user on the machine.