CPU Cache ratio impact on RAM stability

[cniedzi]

Hi,

Does CPU Cache ratio have impact on RAM OC stability or VCCSA on Z390 MB?

[Loadlineac]

No,

The Uncore clock is influenced after my test only by the Vcore.

[Falkentyne]

Hi,

Does CPU Cache ratio have impact on RAM OC stability or VCCSA on Z390 MB?

A too high cache ratio will just generate a "clock watchdog timeout" (0x101), or a Stop 0x124 (WHEA uncorrectable error). Stop 0x124 on these platforms is very often cache related. Clock watchdog timeout can be core or cache, but usually core.

VCCIO affects uncore more than VCCSA (memory i/o), although both also affect the memory controller as well.
Someone somewhere (?) said that one affects frequency scaling and another affects timings stability. But a higher cache ratio also improves memory bandwidth. Keep this in mind.

However, VCCIO controls L3 cache voltage.
L3 runs at the core clock frequency. The issue is that hyperthreaded CPU's make heavy use of the L3 cache for the logical processors. So a too low VCCIO can cause CPU Cache L0 errors to appear. Sometimes stopping these if your cache ratio is too high requires a very high bump in vcore, or a small bump in VCCIO.
A 9700K for example, is far less likely to generate a CPU Cache L0 error than a 9900K. A 9700K tends to just crash the application, or just BSOD with 0x101 or 0x124 (unless you get those weird "Internal Parity errors" or "Translation Lookaside Buffer errors."

[cniedzi]

Thx for info

[Silent Scone@ROG]

Hi, Does CPU Cache ratio have impact on RAM OC stability or VCCSA on Z390 MB?

*Hello, cache speed can have an impact on memory stability, yes. Errors can occur at point of uncore/memory interaction, and are more likely to occur when the uncore domain is being pushed further.

HCI Memtest is fairly good at detecting this type of instability when the uncore domain is being pushed too far.