Originally Posted by Mumak
That's right - only very few CPUs allow true hardware measuring of BCLK (i.e. Skylake). For the rest we need to perform certain (often indirect) measurements to determine the BCLK and this can of course show slight fluctuations, especially under heavy system load.
HWiNFO has an option to disable BCLK "Periodic polling", so it will sample BCLK only once and don't perform periodic measurements and thus show fluctuations. I'm sorry, but there's no other way around this, as long as manufacturers don't offer a true measuring like in Skylake.
Ah I see, didn't actually think of that. But makes sense that those incorrect readouts mostly appear for me when y-cruncher is running the FFT test which creates some minor freezes. Thanks guys!