Random reboot / Crash(?) on AMD Sempron with 9.1-R

[Branden Harper]

Hello,

I'm having an issue with my AMD Sempron box.  It randomly crashes/reboots.
 I have no been able to catch it in the act, I just find the aftermath the
next time I log in.  It does not drop any core files in /var/crash and has
no strange messages in the log files.  I have even built a custom kernel
with KDB and KDB_UNATTENDED options, but there seems to be no traces.

Any tips/help is appreciated.  If more info is needed I will provide what I
can.

Server Information -

FreeBSD chloe 9.1-RELEASE FreeBSD 9.1-RELEASE #0: Mon Feb 11 15:47:59 CST
2013     root at chloe:/usr/src/sys/i386/compile/CHLOE  i386

CPU: AMD Sempron(tm)   2300+ (1579.41-MHz 686-class CPU)
  Origin = "AuthenticAMD"  Id = 0x681  Family = 6  Model = 8  Stepping = 1

Features=0x383fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE>
  AMD Features=0xc0480800<SYSCALL,MP,MMX+,3DNow!+,3DNow!>
real memory  = 805306368 (768 MB)
avail memory = 731676672 (697 MB)

Motherboard: ECS 741GX-m (
http://www.ecs.com.tw/ECSWebSite/Product/Product_Detail.aspx?DetailID=422&MenuID=1&LanID=0
)