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RAM Displays Wrong in Memtest After CPU OC

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a b K Overclocking
May 18, 2013 7:02:41 PM

Memory Spec: GSkill Ripjaws X F3-12800CL8D-8GBXM. DDR3 1600 8-8-8-24 2N 1.5V.

I was able to get my CPU to 4.5 ghz (1.288-1.32V. -0.03 offset, LLC 2, PLL overvoltage: auto. BLCK 100). I moved onto OCing my GPU.

Tonight I was hoping to OC my memory. I decided to load memtest to ensure the CPU OC didn't somehow alter the memory.

I don't know if the CPU OC is to blame or what but everything is way off. Instead of showing BLCK 99%, its now at 75%. 798 mhz DDR3 1596 shows as 603 mhz DDR3 1206.

I tried manually inputting memory spec and frequency in the BIOS, disabled spread spectrum, upped DRAM voltage to 1.65V, and upped VTT to 1.15. Nothing helped.

PC Wizard and CPU-Z show the settings correctly, but I suspect they are just showing what they should run at.

Is this typical? That after a CPU OC the memory refuses to run at spec. even when you manually specify your settings, or is memtest displaying incorrect info, or....? I would have thought that it would give BSODs or crash instead of just refusing to run at spec.

Any help would be greatly appreciated.
a b K Overclocking
May 24, 2013 7:30:09 PM

I apologize if this is common knowledge, but in case it may help other people, I'll share that from what I can gather Memtest 86+ will often display incorrect information after the processor has been overclocked. This is true even with the latest version (which I was using. 4.2 I believe).

Why? I couldn't tell you; there's little info on the matter online, though the small bit there is seems to confirm memtests inaccuracy after a cpu overclock.

It seems that CPU-Z is the best indicator of memory speed, as it updates the frequency (per DIMM) in real time, and confirmed my BIOS settings, as did numerous benchmarks showing increased memory speed.



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a c 345 K Overclocking
a c 1950 } Memory
a c 540 à CPUs
June 9, 2013 5:47:29 PM

Correct, Memtest has bugs in it in how it calculates what things are running at, CPU-Z should provide the true freq you are running at in the Memory TAB along with timings, CR et al...and remember the sticks are DDR (DOUBLR data rate) so you take true freq from CPU-Z say 800 x 2 = 1600 which is effective freq
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a b K Overclocking
June 9, 2013 6:02:34 PM

thanks for confirming that.
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a c 345 K Overclocking
a c 1950 } Memory
a c 540 à CPUs
June 9, 2013 6:18:03 PM

No problem, Glad to help
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