[update] 8GB issues, Tyan 2885 K8W
jd at caltech.edu
Tue Apr 19 01:18:04 PDT 2005
Several times in the past people have mentioned issues with
8GB of RAM on the Tyan 2885 K8W (including myself).
Tyan recently posted a BIOS update (version 2.04) which
corrects some issues in earlier BIOSs improperly computing
To summarize, I had experienced two issues:
1) I had observed panics under minimal load with 8GB with the
BIOS autoconfiguring the memory speed. These problems were
correctable by manually degrading the RAM speed as was
possible with the 2.02 BIOS. Interestingly, memtest86+
did not report issues with the autoconfigured settings.
But this perhaps is not surprising because evidence is
that timings were marginal--some sticks of memory would
work others wouldn't. e.g., I'd see situations were CPU0
seems to handle the 4 stick load but not CPU1. This of
course is sensible due to component variation in a
marginal configuration. The 2.04 BIOS now properly
automatically configures to stable memory settings.
*Note the route of this is that you can get to 8GB using
4 double-stacked DIMMs per CPU. We got into a very
confusing situation because both single (double density)
and double-stacked DIMMs had been purchased and our techs
weren't communicating or paying attention to that in
their problem reports.
2) The second problem involves the onboard broadcom and
silicon images chipset. This problem has only manifested
itself under heavy combinations of network and disk
access. Unfortunately, I've never gotten a good
crash-dump and the problem is hard to reproduce.
I do not see similar issues with the em, ahc drivers.
Nor did I see similar issues with the broadcom and si
hardware under linux
I hope this commentary is useful to people. I apologize for
not having anything definite to report on #2. But the take
away is that nothing is intrinsically wrong with FreeBSD
5-Stable on Tyan K8W (S2885) with 8GB--though something
might be lurking in the onboard peripherals.
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