Continual Freezing, Disk Passing

I just can't wrap my head around this one.

Windows 7 Pro on an iMac 14,1. No do not tell me anything about Bootcamp, reproduced on a flat install with latest vendor drivers.

Initially this looked like a bad disk so I ran an extended self-test. Passed and SMART values actually looked quite good, nothing near maximum values and nothing remapped.

What keeps bringing me to disk is... A) This is exactly how a system acts when the drive has no spare sectors but needs to remap. Counterpoint is that this seems to intermittently be all applications and files instead of a specific subset of files. Not really a counterpoint if something is up on the disk and part of windows itself is stored there. B) When frozen, disk holds 100% active with no disk read/write then balloons for a few seconds to in excess of 250MBps then typically freezes again or starts normal operation. C) When frozen taskmngr and resmon graphs keep counting (and graphing) the seconds and displaying no CPU, memory, or disk access (still 100% active though). Once in a while these two tools freeze too, buts that appears to be based off me taking actions that require disk access.

My big problem here is it's not just exploder freezing, all the system monitoring tools whether local or remote have massive delays or just flat out fail. Short of actually swapping hardware until the issue goes away I'm not sure what next steps should be.

I have not noticed the time skewing. That said deep dives into event logs are quite a procedure in this state, i could totally be missing them.

I did also see something that I'm not sure what to make off. Ran ATTO (yes from the system drive on the system drive...) and the test took at least 10x as long as a normal test but produced speed results directly in-line with expected performance. It's been a while since I tested a live system drive, but 10x sounds wrong and I didn't get massively degraded results like it was in an access loop.