Hi all!
I'm experiencing some weird problems with my machine. I've got two IDE PATA drives on separate cables. It worked flawlesly for about 3 years, now there are CRC errors after copy operation between partitions belonging to one disc, or between both drives. I mean, copied files differs from original - I use md5 sums to check it.
I removed all optical drives, replaced IDE cables, checked bios settings, checked temp of drives and cpu, checked surface of both drives using mhdd, checked smart attributes (there are 3 ultra ata crc errors shown on one drive, but none for other, all rest is ok), thoroughly tested ram with memtest+ (12 hours) , tested cpu with prime95 (12 hours). no errors found.
Both drives work good on other machine, no errors at all.
PSU is good, Enermax 560W, working flawlessly for about 5 years. I don't know how to check it, but I will try to replace it for a while - but first I need to get another one

There's no software problem - I've experienced bad checksums under both WinXP and Linux.
What else should I check to solve this issue? Is it possible for integrated IDE controller to fail "just so"? I do not have other ideas

Any help will be appreciated, thanks in advance.
Hardware: nForce4 Gigabyte K8-NF9, IBM/Hitachi and Caviar drives, athlon64, not overclocked.
My exact config looks as following:
1st channel: Master: IBM/Hitachi HDT722516DLAT80, no slave
2nd channel: Master: Caviar WD1200JB, slave: Toshiba DVD-ROM
and one Pioneer SATA DVD writer.
greetings from norway!
Jakob