[SLL] is my slowdown due to hardware?

[William Kreuter]

I'm running the commercial statistics and database
package SAS 9.1.3 on Redhat EL-4, this on a 64-bit
desktop from Silicon Mechanics which just went out of
warranty.  This week I was given an assignment to
re-run a few SAS programs from last year, with a
trivial modification.  The re-runs have taken two to
four times longer.  Since the original running, my
entire Raid cluster of three drives was replaced
because all the drives had gone bad.  The replacement
drives are, I believe, identical models.  The Raid
controller wasn't replaced but it got a firmware
upgrade.

It's conceivable that there's some run-time parameter
that I'm not thinking of which could explain the
slowdown, but I feel doubtful that something like that
would cause this big an effect.  Yesterday I killed
some zombie processes, or at least I think that they
were zombie, when I looked for culprits; could
something like that really choke things up?

How in general does one go about ruling out that it
could be any factor other than creaky hardware?  And
what would be the hardware problem?  Drives spinning
too slowly?  CPU not clocking right?  Grubby RAM?  My
knowledge of hardware and o/s arcana is minimal.

Billy