You made my day. Lol
All software sensors can be assumed wrong. And as someone else mentioned, believe what you like. For an overclocker like yourself, the highest reading would be something you'd be most interested in. It doesn't quite matter if it just spiked there for a couple of seconds (and never does it again), you just want to be prepared for the worst.
If you really have the need to push your computer to the very limits of its engineering, be prepared to spend a few hundred dollars on very picky hardware to measure your temps. They won't be too easy to use, not to mention the need to calibrate them before every use.
BIOS temps have been mentioned to be the most accurate, but remember, it all depends on where they have positioned the probe. The ideal place would be somewhere on the CPU itself, although I have this suspicion its going to be on the motherboard itself, albeit just below the CPU. Bear in mind I have absolutely no idea at this point where any particular motherboard would position their temperature probes, or if CPUs have them built in. Its never been a big point to me: I just take the highest temp measured in Intel TAT, AND a second probe on the heatsink itself just beside the CPU (I assume this probe shows a lower temp. I just haven't ascertained how much lower).
Given that I'm an enthusiast, getting the temperature correct to the 0.5C doesn't quite bother me. As long as none of the probes go too high, or my computer becomes unstable, its not going to bother me.