>> (I'm on a SPARCstation 2 with a Weitek PowerUp chip now, if that matters.)
> 
> I've been thinking about getting one of these, does NetBSD work OK on it?

Like a champ.

> And is there a performance boost?

You betcha.

> Does NetBSD detect it?

Nothing to detect.

It's reported as

cpu0 at mainbus0: SUNW,Sun 4/75 (W8601/8701 or MB86903 @ 40 MHz, on-chip FPU)
cpu0: trap page uncached
cpu: 65536 byte write-through, 32 bytes/line, hw flush cache enabled

I would suspect there's no way to know it's in there, much less the internal
clock doubling.

You can get them for $750 US now.  I highly recommend it if you want to keep
the old boxes around.  In my (work) environment, I suffer from the "hand me
down clothes" syndrome (I'm the only live human in my main group that I work
for half-time who doesn't have a SPARCstation 20, and the other 5's/10's/20's
are used for Real Work, so I couldn't have one of those anyway even if I
wanted to run SunOS instead).  So I have to scrounge what I can get.  Until
a sun4m port is forthcoming (getting NetBSD to go on a SPARCstation LX or a 5
first would probably be a good candidate, as those are the next likely models
to be available to anyone in a similar "hand me down clothes" environment),
this seems like a fairly reasonable setup for now.  I'm chuffed  :-)

	- Greg