X on 3120/3130: is it possible/worthwhile?

[HCART at VAX.OXFORD.AC.UK]

   Our undergraduate lab is about to be given a 3120 with 380 meg
disk.  IRIX for the machine has not been updated for at least a
couple of years, as far as I know, since I don't think it was
on a software maintenance contract, so I'm considering what
updates might be worthwhile.

    I would really like to use the 'new' 3120 (or an existing 3130)
as a client running X windows to a Sun running Uniras under X windows.
Questions:

    Will a 3120/3130 happily run X?

    If so, will it run at a halfway decent speed?

    Am I right in thinking I need 3.3.1 to run X?  What is its cost
    (plus anything else I would need to run X windows)?

    All advice welcome.

    Hugh Cartwright.
    Physical Chemistry,  Oxford.