grep -r speed fc2 vs. rh 6.1

[Gene Smith]

I have the same huge source tree on fc2 500Mhz Athlon with IDE drive and 
on a old hp vectra 200Mhz with Pentium pro and scsi drive running rh 6.1 
with ext2. A "grep -r" for the same string on the vectra takes about 
about a third as long to return results as compared to the somewhat 
"faster" Athlon/IDE/ext3 system running fc2. However, building the tree 
(and most everything else) takes longer on the vectra by a noticeable 
amount.

Both are running grep from a kde "konsole" in their respective kde 
environments. Is it possible that fc2 gives grep and possibly similar 
commands a lower priority than rh 6.1 gives? Or is it the scsi drives or 
ext2 (on rh 6.1) vs IDE and ext3 I am using on fc2?

Any ideas?

-gene