severe performance degradation on serverworks with high mem

["Brian C. Thomas" <bcthomas@nature.Berkeley.edu>]

Hi

I have a Supermicro S2QR6 board, which has the "Serverworks serverset
III HE" chipset.  (Also, i have 8GB RAM, 4 Xeon P3 700MHz processors,
and an Adaptec Ultra160 SCSI system - aix7xxx, built onto the 
motherboard)

In all the 2.4.x series kernels (even up to 2.4.12-ac3 or
2.4.13-pre4), as soon as the high memory, 64GB option is enabled, the
server slows down to a crawl, with no load showing.  (A "crawl"
example is a kernel recompile time going from ~5 min to >2 hr!)

I have tried numerous kernel config options, removing scsi support,
networking, and have narrowed the problem down to the serverworks
chipset- on a SC440NX mb, also with 8GB and everything else in the
system, all the new kernels work with no slowdown.

I've tried...
kernels: 2.4.1, 2.4.3, 2.4.5, 2.4.7-ac9, 2.4.9, 2.4.12 (-pre4, -ac3)
with and w/o mtrr support kernel config

Any ideas?

Thanks,

BCT

____________________________
Brian C. Thomas
bcthomas@nature.berkeley.edu