#Buying a new PC
Robin,
For normal (boring) applications, both computers are about the same in speed
(probably the same in price as well). What makes the Pentium a better choice is
its better performance in floating point processing and a pipelined
architecture. Both Autocad and 3D Studio use considerable amount of floating
point math and can take great advantage of the Pentium. The pipelined
architecture will be important for applications that make use of it. This
means, for applications specifically optimized for the Pentium. As you are
buying a machine to last for a while, this is a strong point as more and more
support will be given to this "pipelined architecture". NT for instance is
optimized for the Pentium and takes full advantage of it.
Regarding your video card options, I don't like either. There isn't, in fact,
something out there I like yet. This is too new. The Viper is ok. Diamond, on
the other hand is a nightmare when it comes to support. Matrox is too far for
serious support (East coast – Canada) though some people here like them. Either
way, the Matrox is useless for 3D Studio as there are no drivers for it.
Go for the 2Gig SCSI-II drive. There are no compatibility issues.