SIS 630E perf problems?

[Larry McVoy <lm@bitmover.com>]

I use bookpcs - all in one, really nice form factor - for build machines,
firewalls (with a USB ethernet), etc.  I used the first generation which
had intel i810 graphics (sucked) but had fairly typical performance, 
competitive for kernel builds with other current platforms at the time.

I recently bought a couple of the second generation of these boxes, these
have an SIS 630E based motherboard.  This has a much better graphics interface,
quite reasonable at 1280x1024, and all the other bits work fine under RH 7.1
without tweaking.

Performance sucks, however.  I did an LMbench run to try and figure out why
and it's obvious - the memory latencies are 430 ns - that's 2x more than
what is reasonable.  I tweaked the various bios settings a bit and could
not get it to change much, maybe 20ns but not the 200ns I was looking for.
The fact that this system is running a celeron with a dinky cache makes it
feel really slow.  These boxes with a 633Mhz celeron feel slower than the
old boxes with a 400Mhz celeron.

All I want to know is if this is in fact the real memory latency for these
motherboards.  Anyone know for sure?

Here's what I could dig out of /proc:

PCI bus devices:
    Host bridge: Silicon Integrated Systems [SiS] 630 Host (rev 32).
    IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE] (rev 208).
    ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513 (rev 0).
    Ethernet controller: Silicon Integrated Systems [SiS] SiS900 10/100 Ethernet (rev 129).
    USB Controller: Silicon Integrated Systems [SiS] 7001 (rev 7).
    USB Controller: Silicon Integrated Systems [SiS] 7001 (#2) (rev 7).
    PCI bridge: Silicon Integrated Systems [SiS] 5591/5592 AGP (rev 0).
    Multimedia audio controller: C-Media Electronics Inc CM8738 (rev 16).
    Communication controller: C-Media Electronics Inc CM8738 (rev 16).
    VGA compatible controller: Silicon Integrated Systems [SiS] SiS630 GUI Accelerator+3D (rev 32).