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Tranquil_Ape · ‎05-13-2014

So I built a new PC last month and currently have 4 sticks of Corsair vengeance pro installed (CMY8GX3M2A2400C11R)

It seems like every time i enable xmp (everything else at optimized defaults) the machine feels unstable, I can't get through one succesful pass of a realbench stress test (side note... any other recommendations for this sort of testing? just curious).

if i turn XMP off and run the memory at 1333 everything seems to run well. I plan on going through the Memory Setup Guide For Maximus VI Motherboards when I get home today in hopes that things may clear up, but I wanted to see if any of you knowledgeable folks were able to add anything that would help me out.

Appreciate any info that you can offer. Thanks.

jab383 · ‎05-13-2014

Hi, Tranquil Ape

RAM overclocking often needs a few other tweaks. The guide you reference is a good one. Pay attention to "method 2" - manually inserting the XMP frequency and timing. That lets you work with some of the other BIOS settings.

Some CPUs need a small boost to System Agent voltage in order to work at DDR3-2400. Try Vccsa of 1.1 to 1.2 volts (if in 'fully manual') or an offset of 0.25 to 0.30 volts (if using offsets.) Likewise CPU Analog I/O 1.05 to 1.1 volts, about .050 to .100 offset. CPU Digital I/O of 1.1 to 1.2 volts, about .100 to .150 volts offset.

Realbench is quick, easy and available. It's also fun to compete on the leaderboard. An OC profile that completes the Realbench benchmark will do most things a user needs. I say 'most.' I have run into bluescreens at inopportune times in Adobe CS6 with profiles that pass Prime95 or Realbench.

I have found that OCCT is more a more stringent and more effective test. No OC profile that passes 3 minutes of OCCT Large Data Set test has ever thrown a bluescreen at me. My 24/7 profile will always be stable in OCCT.

That doesn't apply to benchmarking. A profile that completes the benchmark is stable enough by definition. I have found that many benchmarks will run 100 to 200 MHz higher clocks than will pass OCCT.

Jeff

Tranquil_Ape · ‎05-13-2014

Really appreciate the info Jeff, every little bit helps. I will have to go through and learn what these different voltages control specifically but I find that its easier to understand/retain why the settings work when I have an idea of what they do. Can all of these settings be found in the uefi or do i need to install the AI suite III software ?

jab383 · ‎05-14-2014

They're all in the UEFI. I do not have AI Suite installed.

Jeff

Tranquil_Ape · ‎05-14-2014

So I started work on this last night... method 2 gave me a little trouble at first... looking at the ASUS SPD table in the Tools area showed me different timings then what the xmp profile had. After a few resarts I figured that out... then on to the voltage changes you mentioned... setting the SA, aI/O and dI/O via offsets has yielded some promising results.

One of two things would happen... crash or BSOD would occur just as windows was loading up, sometimes it would get as far as the log in screen but usually during the colored floating balls. I would incrementally increase the voltage and try again. QUESTION: Since I didn't know any better I have been increasing all three of these roughly the same percentage each time i needed to increase them. Should I continue this or is there a better way to approach it? My current plan is that once I get it passing benchmarks/stresses to back off each one individually in order to fine tune... if i see behavior i don't like after a decrement, I know to go back up one and then move to the next voltage (does that make sense?)

So it got late last night and I ended up leaving off what I think will end up allowing me a stable realbench pass. (should be able to update tonight with final numbers (fingers crossed). My realbench passes started off crashing during the second phase but now they are consistently crashing during the heavy multitasking portion, I managed to get through that test last night a couple times with no problem before calling it a night. I'll start tonight by attempting to run a full pass or three and then move on to occt.

Now... If i understand correctly... the System Agent voltage is what is fed to memory controller, pcie controller and the onboard graphics controller? and the I/O voltages are for the interaction between mobo, ram, pcie, etc. ? is this (layman's) accurate?

M6F - Corsair Memory (XMP) problems