You're contradicting yourself or don't understand the value of precise communication. That "triviality" is hundreds of megabytes per second. Yet you say replacing components with worse performing ones is bad. That "triviality" has the same effect.
That could be a power supply issue (not necessarily PSU tho, could be VRM too). Have you tried fiddling with loadline for example (because maybe the voltage drops too much under load)? I don't see what could cause BSODs after a certain *time*. Try stress testing, it's easier to debug max load...
The readings are not guaranteed to be correct. If nothing seems off (and this is your first data point instead of the indicated temp having been normal before) I'd ignore it as obviously wrong. Either that or you have a short in the fan.
Heat is going to be a real problem when the 18 core SKUs come out regardless of Prime95. There are other AVX heavy use cases you know and the headroom will decrease with each additional core. Right now I'm quite satisfied that I went with Broadwell.
I'm willing to bet that WD's 80 GB drives were nowhere *near* the worst drive even in their era (*cough*Maxtor*cough*), and that's not even getting to drives that were mostly DOA (can't remember the mfr, they went bust shortly after).
@Blackbit75, I bet most sub-1080p displays are from phone browsers, and most of the rest are laptop screens, neither of which are relevant wrt add-on GPUs.