What's the realistic upper frequency limit of the cache / uncore, for Haswell K, Haswell-E, and Skylake-K?
The reason that I ask is, I can clock my G4400 Skylake dual-core to 4.62, using 140 BCLK, and 1.400V, and it will even pass 10 minutes of OCCT:CPU. But then, within an hour or two, it will throw a "watchdog_clock_timeout" BSOD.
My working theory is, that with a BCLK OC, both the core clock and the uncore / cache clock multipliers are set to max possible (33x, in the case of the G4400), and then you OC using BCLK, which can tend to push the cache faster than it can handle, even though the CPU core(s) themselves could go higher.
I saw mention of a 6700K OC in a guide, that they had their cache / uncore multi at 41x, when they pushed their core clock multi to 47x, at 1.408V vcore.
So I think that the cache / uncore, doesn't really want to go up to 4.5Ghz or beyond.
My G4400 has been happy for nearly / over a year now, at BCLK 135.0, 4.45Ghz, vcore 1.300V.