File corruption on uploaded files occuring (even under light load)

[Stefan Haglund]

I have an IWILL KK266-R (VIA KT133A/686B) board with an 1.4GHz processor 
running as a FreeBSD file & web server. The NIC is an Intel EtherExpress 
PRO/100 (I think it's called, fxp anyway). This board has an AMI RAID 
controller (CMD 649) onboard, which I use for all four drives (although 
not in RAID).

My problem:
Files uploaded to this server are sometimes corrupted. It doesn't have 
to be under high load, like directly uploading from a computer. It can 
also occur when I'm downloading from the internet on a computer, and 
save the file to the server. Another thing that is wierd, is that when 
the computer is fresh from a boot, there is always a few netstat Oerrs 
(5-30 I've seen this far) errors occuring when downloading or uploading, 
and never again.

I have run mprime stresstest for a good while, with no complaints. I 
have also tried another NIC, and also moving the NIC to other PCI slots. 
I've tried with kernels without APIC, tried disabling ACPI, and I've 
also disabled throttling. My friend is running a similar setup on his 
server, although a KT266A chipset, and no RAID controller (southbridge 
IDE), and it is solid as a rock.

Anyone have any ideas what might be causing these corruptions? Chipset? 
NIC? RAID controller?

Regards,
Stefan Haglund