p67 fatal1ty professional 4 memo starting at 1333

grigorym wrote: Has anybody met such a problem? I've got ASRock P67 professional fatality with core i7 2600K without any overclocking whatsoever, with a 2x4GB Corsair Vengeance 1866MHz (CMZ8GX3M2A1866C9). Recently i've decided to add some RAM, bought the same one only with a "B" suffix (CMZ8GX3M2A1866C9B), the blue one. I have now all four slots filled, but the system fails to start at default 1866MHz. All BIOS setting are at their default AUTOs. It starts twice for a second and turns off. On the third time it starts, but BIOS and CPU-Z show it works on 1333MHz. Any pair of my memory modules start at 1866MHz nicely, but not all four at the same time. Could anybody give me any hint of the direction to search in? I've never bothered to learn about asrock memory issues, since it was ever working like charm. The page in the manual suggests nothing but that all four modules should be identical. Mine are identical seemingly, but the color - but that shouldn't cound, should it?

The double start and stop, and third time start into the BIOS is the Boot Failure Guard option working. The associated Boot Failure Guard Count option is probably set to three. They are in the Boot screen.

This option will let the board attempt to POST N - 1  times, where N is the Boot Failure Guard Count value. If the last try to POST fails, you are put in the UEFI to fix whatever the offending setting is, which is set automatically to a functional value or setting.

In your case, the four DIMMs will not POST at 1866 is what is most likely happening. Several possible reasons why that is happening.

The i7-2600K is guaranteed to work at a memory speed of 1333. Any memory speed beyond that is an OC, so depends on how good the memory controller (IMC) in your CPU is (among other factors.) Just like a processor OC, memory OC varies, all CPUs are not identical in these respects. So the maximum over clocked memory speed rating of any memory is not guaranteed to work.

Using more DIMMs (four instead of two) or more capacity with two DIMMs (two at 8GB vs two at 4GB) is also more difficult for the IMC to deal with, more so when over clocked.

You are using two unmatched sets of memory together. While they may be the same model, the binning of the memory chips, or even the memory chips may be different in each set of memory. It is possible that the SPD data (timing and other settings programmed into the memory, like an XMP profile) may be different between the two sets of memory. That is a standard situation with memory "manufactures" that do not make their own memory chips. Most memory manufactures don't make their own chips, including Corsair. The farther apart of the time of manufacture of each set of memory, the more likely it is they will be

Two unmatched sets of memory might work together at a lower speed, but not when over clocked. All of these things apply to any type of memory, and are unrelated to a mother board issue. The ability of a mother board to operate memory at high speeds is related to its design and build quality, but we can't change that.

Things you can try:

Did you clear the BIOS/CMOS when you added the new memory? That should be done after any major hardware change, such as adding or changing memory.

Use each set of memory in one memory channel. When people get a new set of memory, they just add it to the unused slot of each channel, mixing the two sets. Keeping the two sets in their own channel can help.

You may need to set the memory timings all to AUTO to get all the memory to run at 1866. If it will run at 1866 like that, you can then try to set the timings manually, since the Auto values will most likely be slower.

Did you increase the DRAM voltage after adding the new memory? If not, try increasing it to 1.6V.

Try increasing the VCCSA Voltage in the BIOS somewhat, but not to the maximum. The same for the VTT voltage.

I doubt that the default speed of your memory is 1866, for DDR3 memory. If you have the XMP profile enabled, that is not the default speed.