Every now and then, about 15-20 minutes in between, this computer will 
stall.  For about 5-7 seconds, the HD LED will come on solid, I'll hear 
the HD click once like a full stroke, the monitor will blank, all 
keyboard and mouse activity stalls, and any sound stream will do a 
~.75second buffer repeat for the length of the stall.

After the stall is done with, -some- keys pressed may be sent to the 
application, not all will.  No mouse movements or button presses will be 
reported, the HD LED turns off and the monitor comes back to life.

This happens regardless of computer usage patters and nothing is 
reported in dmesg.

It's an SK8V motherboard, Opteron 148, 1G dual DDR400.

Scott root # lspci
0000:00:00.0 Host bridge: VIA Technologies, Inc.: Unknown device 3188 
(rev 01)
0000:00:01.0 PCI bridge: VIA Technologies, Inc.: Unknown device b188
0000:00:07.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host 
Controller (rev 80)
0000:00:08.0 RAID bus controller: Promise Technology, Inc.: Unknown 
device 3373 (rev 02)
0000:00:09.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875J 
(rev 04)
0000:00:0a.0 Ethernet controller: 3Com Corporation: Unknown device 1700 
(rev 12)
0000:00:0c.0 Communication controller: Conexant HCF 56k Data/Fax Modem 
(rev 08)
0000:00:0d.0 Ethernet controller: Lite-On Communications Inc LNE100TX 
(rev 20)
0000:00:0f.0 RAID bus controller: VIA Technologies, Inc.: Unknown device 
3149 (rev 80)
0000:00:0f.1 IDE interface: VIA Technologies, Inc. VT82C586/B/686A/B 
PIPC Bus Master IDE (rev 06)
0000:00:10.0 USB Controller: VIA Technologies, Inc. USB (rev 81)
0000:00:10.1 USB Controller: VIA Technologies, Inc. USB (rev 81)
0000:00:10.2 USB Controller: VIA Technologies, Inc. USB (rev 81)
0000:00:10.3 USB Controller: VIA Technologies, Inc. USB (rev 81)
0000:00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
0000:00:11.0 ISA bridge: VIA Technologies, Inc.: Unknown device 3227
0000:00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233 
AC97 Audio Controller (rev 60)
0000:00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 NorthBridge
0000:00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 NorthBridge
0000:00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 NorthBridge
0000:00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 NorthBridge
0000:01:00.0 VGA compatible controller: nVidia Corporation: Unknown 
device 0322 (rev a1)

Scott root # cat /proc/interrupts
           CPU0
  0:  176550676    IO-APIC-edge  timer
  1:     109155    IO-APIC-edge  i8042
  8:          0    IO-APIC-edge  rtc
  9:         47   IO-APIC-level  acpi
 12:       9272    IO-APIC-edge  i8042
 14:     822159    IO-APIC-edge  ide0
 15:         80    IO-APIC-edge  ide1
 16:         42   IO-APIC-level  sym53c8xx, ohci1394
 17:    2586129   IO-APIC-level  SysKonnect SK-98xx
 18:       6737   IO-APIC-level  intranet
 21:   30678864   IO-APIC-level  ehci_hcd, uhci_hcd, uhci_hcd, uhci_hcd, 
uhci_hcd
 22:    1460310   IO-APIC-level  VIA8233
NMI:      25073
LOC:  176534397
ERR:          0
MIS:          0

Scott root # cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 5
model name      : AMD Opteron(tm) Processor 148
stepping        : 8
cpu MHz         : 2211.088
cache size      : 1024 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext lm 
3dnowext 3dnow
bogomips        : 4341.76
TLB size        : 1088 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management: ts ttp

David