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Let me just preface my post by stating that I am not at all experienced with RAM overclocking, I never really bothered and everything I've read seems to indicate that RAM speed doesn't have much impact on performance. I do want to be able to use the speeds I paid a premium for though, regardless of performance impact.

Here is the RAM.

Corsair Vengeance 2400Mhz DDR3.

It wasn't significantly more expensive than the other options I was considering at the time so I figured I'd go for the faster option, since this will probably be my final purchase of DDR3. I also figured that RAM rated for 2400Mhz is probably of higher quality than average.


However, my system simply fails to boot when I set the XMP profile. It'll run through 3 (or so) failed boots until the MOBO decides to revert the changes, and back to 1333 it goes. I have it manually overclocked @1866Mhz using slightly higher timings than stock at the moment, perfectly stable as far as I can tell. It will boot but is fairly unstable at 2133Mhz (using the timings from the XMP profile). It simply won't boot at 2400Mhz no matter what timings I've tried so far. I bought the RAM a couple months ago and have just dealt with it @1866 since then after messing about with it for a few hours and giving up.

My google-fu seems to have failed me, but from what I could gather it seems possible the 3570K might not be able to handle 2400Mhz? I couldn't find any confirmation on that though. Like I said, not very experienced in this area.

One thing I should note is that due to the stupidly large heat spreaders, my HSF blocks the normal config for dual channel, meaning I have the second and 4th (from the CPU) slots filled instead of 1st and 3rd. I did some quick research and everything I could find seemed to indicate that it didn't matter much if they were offset like that FWIW.

Any suggestions for making it work at the rated speed, if possible? At lower speeds it is perfectly stable as far as I can tell, though I have not run any memory testing software of any kind.

You might need to manually increase the voltage from 1.5volts to 1.525-1.55 for stability.

If your running Windows the built-in Windows Memory Diagnostic program is a quick way to check for stable operation.

The motherboard or memory controller probably doesn't like settings under XMP profile at 2400Mhz. I would dial things back and try to see if that works and run some Memtest86+ for a run or two.

The last/3rd memory diagnostic setting is really slow. (Win 10, search bar, diagnostic). First two, will tell you if something horribly or physically wrong pretty quickly. Than its better to just run a stress test or benchmark inside Windows instead of artificial memory test. Getting everything hot and push power supply to possibly supply dirtier power. More realistic test if memory subsystem is on edge of OK.

Check your motherboards website if that kit is specifically certified or not.
Also check manual, pretty common for Z boards to only certify higher speeds in specific pair, and the absolute highest in just one slot and show absolute limit of board.

For example: http://www.asrock.com/mb/Intel/Fatal1ty ... cat=Memory
Note1: It is recommended to install a memory module in DDR3_A2 or DDR3_B2 slot first!
Note2: 4PCS = dual channel, supports 2 modules and 4 modules
Note3: 2PCS = tested successfully with 2 modules
Note4: The O.C. mode is not guaranteed. It depends on whole system configuration and other parameters.
Note5: For system stability, use more efficient memory cooling system to support a full memory load (4 DIMMs) when overclocking.
Note6:Due to the configuration of CPU, the default speeds of DDR3 2333/2300 MHz will operate at DDR3 2200/2200 MHz.

memory speeds beyond the specs given for a cpu are the luck of the "silicon lottery" and are not guaranteed and its all up to how good the memory controller is on your cpu if you are able to get high memory speeds
the 3570k is only rated for 1600mhz memory speeds - going higher means you are effectively overclocking the memory controller and just like overclocking a cpu's speed it all depends on your "silicon lottery" luck on how far the memory controller will go

how fast the memory can go has very little to do with the motherboard and pretty much fully depends on how lucky you are with the memory controller you have on your cpu
some of the top overclockers go through dozens of cpu's just to get ones that can do ultra high speed memory

that said if you are having trouble with the memory controller being able to do the memory speeds of the memory you have you should bump the voltage on the memory controller in the settings
for example the memory controller on my 3930k has troubles above around 2200mhz unless i up the voltage to around 1.2v on the memory controller

f0d wrote:

memory speeds beyond the specs given for a cpu are the luck of the "silicon lottery" and are not guaranteed and its all up to how good the memory controller is on your cpu if you are able to get high memory speeds
the 3570k is only rated for 1600mhz memory speeds - going higher means you are effectively overclocking the memory controller and just like overclocking a cpu's speed it all depends on your "silicon lottery" luck on how far the memory controller will go

how fast the memory can go has very little to do with the motherboard and pretty much fully depends on how lucky you are with the memory controller you have on your cpu
some of the top overclockers go through dozens of cpu's just to get ones that can do ultra high speed memory

that said if you are having trouble with the memory controller being able to do the memory speeds of the memory you have you should bump the voltage on the memory controller in the settings
for example the memory controller on my 3930k has troubles above around 2200mhz unless i up the voltage to around 1.2v on the memory controller

^ This.. Try to find the memory controller voltage setting and increase it, that might help.

Thanks, I'll try these suggestions now and report back, in the meantime feel free to pile on with more ideas.

I forgot to mention my motherboard, I checked before buying the RAM to make sure it was 2400Mhz capable, and the spec sheet on the site says it does, for what that's worth.

Biostar TZ77A product page.

I manually set RAM to 2400Mhz and tried the following so far:

I overvolted the "system agent", which in the description says it controls the memory controller, only by 2 "notches" as I don't want to do any damage with my ignorance, and from my experience with CPUs, overvolting can have a fairly heavy affect on heat and power consumption. I also tried overvolting the RAM, up to 1.65v and slightly beyond, 2 "notches" beyond (1.65v is what the XMP profile sets). I tried relaxing the timings even further than the XMP profile as well. All of these things combined and still can't POST. That includes removing the undervolt I have applied on the OC'd CPU itself.

I think it is somewhat unlikely that the PSU is supplying dirty power, my total system power is almost certainly far less than the 750w platinum EVGA PSU I slapped in somewhat recently can supply.

Windows memory diagnostic returned no errors as far as I know (@1866Mhz). I'll try other diagnostic tools later if need be.

I'll post the XMP timings, as well as some of the ones I tried later as well.

I'll try some more suggestions after I get some sleep. Thanks everyone for the help.

f0d wrote:

memory speeds beyond the specs given for a cpu are the luck of the "silicon lottery" and are not guaranteed and its all up to how good the memory controller is on your cpu if you are able to get high memory speeds
the 3570k is only rated for 1600mhz memory speeds - going higher means you are effectively overclocking the memory controller and just like overclocking a cpu's speed it all depends on your "silicon lottery" luck on how far the memory controller will go

how fast the memory can go has very little to do with the motherboard and pretty much fully depends on how lucky you are with the memory controller you have on your cpu
some of the top overclockers go through dozens of cpu's just to get ones that can do ultra high speed memory

This pretty much.

I even have a Haswell 4790K that cannot run 2400Mhz stable. Sometimes it passes 8+ hours of Prime95 stable, other times it pops errors within seconds with the CPU at stock. I fiddled with voltages and some of the timings but because of how intermittent the instability was it was a pain to do any stability checking with it. It could even pass Memtest runs most of the time. Eventually I just left it at the second XMP profile for 2133, the performance difference is negligible and I value system stability much more than 267mhz.

After fiddling with it a bit more, I suppose I'll just settle in at 1866 and get comfortable. I regret the heat spreaders more than being unable to run it at 2400, though. The price difference was negligible compared to other "fast" RAM, so I'm not too upset, all things considered.

Let this be a lesson for others though, make sure your CPU can handle your RAM's advertised speed before purchasing.

Since you in theory have good modules, instead of pushing the frequency, you can geek out over the timings.