i5-6600K, ASUS Z170-A Overclocking

[philipew]

Cache has to be "at or below" CPU Core Ratio (frequency). At a stock value of CPU Core = 3.5 GHz, the cache is at 3.5 GHz and all is fine. At higher frequencies however like when overclocking, the frequency is much less stable. So for example if you set the cache freq. at 4.8 GHz with a CPU Core freq. at 4.8 GHz, it will not remain "at or below" 4.8 GHz but is likely to spike "over" 4.8 GHz causing a BSOD crash (blue screen) with a timing error (like for example TIMEOUT_WATCHDOG_ERROR).

So the solution is to set the cache freq. "one under" the CPU Core freq. For example, cache at 4.7 GHz for CPU at 4.8 GHz, cache at 4.6 GHz for CPU at 4.7 GHz, etc. The difference in performance will not be "up there" but stability will be better and power (= temps) may also benefit. Cache is working hand in hand with the CPU to store "transient" data. Having the cache working about as fast as the CPU prevents the CPU from having to wait for the cache to deliver the transient data.

N.B. My Gigabyte UEFI (when accessing the BIOS) 'wrongly' stipulates that the cache should be at of higher than the CPU Core freq. This is already no longer the case the moment you start raising the CPU Core freq. as the cache remains for ever stuck at its 3.5 GHz initial value, and yet it doesn't give any problem. So they should change that comment to "at or below" CPU Core freq. IMO.

 

[wingman99]

At or below CPU Core frequency is what my Gigabyte motherboard says for uncore. Uncore frequency only works with L3 Cache not L2 or L1 with i5 and i7, so it is not that important.

Uncore functions include QPI controllers, L3 cache,[a] snoop agent pipeline, on-die memory controller, and Thunderbolt controller.[3] Other bus controllers such as PCI Express and SPI are part of the chipset.[4] https://en.wikipedia.org/wiki/Uncore

What motherboard do you have?