1

I have been struggling for the last few days with my new PC set-up consisting of a:

MSI X99S Gaming 7 Mainboard
i7-5820K CPU
G.Skill DDR4 3000mhz (F4-3000C15Q-16GRR)

The issue is that once I enable the XMP Profile on my Mainboard (latest BIOS revision) the Mainboard automatically sets the CPU base clock from 100mhz to 125mhz. The system then becomes extremely unreliable and crashes very frequently. Once I disable XMP and reset the BIOS to default settings I can run the RAM at 2133mhz without any issues and the System is quite stable.

But still I'd like to get the full 3ghz performance out of my memory modules. It seems the issue is that only the clock is increased (thus overclocking my CPU) but other settings to offset this increased clock speed are not set by the XMP2 Profile.

Unfortunately I have never bothered with overclocking before so I have no clue how to manually adjust the CPU to run at a stable speed with the base clock @ 125mhz.

Can anyone help me explain: a) Why the RAM needs the CPU to run @ 125mhz b) How I need to adjust the multiplier to get it back to the 3.3ghz it can run safely?

The Mainboard is running the latest BIOS update (17.10 also called Release HA)

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It seems I have solved this mystery.

After running with disabled XMP for quite some time now I noticed that whenever my CPU ran in Turbo-Mode my RAM speed as reported by CPUID was at my desired 3000mhz.

After checking again in the Bios I noticed that the XMP profile does overclock the CPU correctly, but does not disable turbo-boost. So whenever Windows requested more Power from the CPU it would overclock itself a second time although it's already running at a higher clock.

So the solutions would be to either disable Turbo-Boost so the CPU is always running at max clock speed - or keep the XMP profile on and profit from the Energy-Saving settings while having the full performance available whenever the system decides it needs the Boost.

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Im guessing that you're using a x99 mobo and these mobos raise the CPU base clock from 100mhz to 125,03 mhz when using ramspeeds above 2666mhz. I use the XMP and get 3000mhz and when it changes the CPU base clock to 125mhz I manually change the multiplier to 36 (125*36=4500) to get 4,5ghz and increase the voltage to 1,325 to compensate for it. Been working like a charm for some time now, idle temp is around 37C and during load it reaches 73C (H100i GTX water cooling).

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