Intel Motherboards : Memory Error with Dual Quad Kits, None with Single

Author: parsec
Subject: Memory Error with Dual Quad Kits, None with Single
Posted: 19 Feb 2016 at 3:00pm

Some information and a correction and then comments and more information.

Your board and CPU supports Quad channel memory. The four memory channels are labeled A, B, C, and D.

Each memory channel has two slots, and can accept two memory DIMMs per channel. The memory slots are labeled A1 A2, B1 B2, C1 C2, and D1 D2.

Note that EACH memory channel has one red slot and one black slot. For example, slot A1 is black, slot A2 is red.

You purchased two, 4 x 8GB kits of memory. Each kit is considered a matched set. The two kits are not matched sets.

You installed one matched kit in the black slots, and the other matched set in the red slots. The result is two unmatched DIMMs in each channel.

Since both kits tested fine individually, but errors occur when the kits are mixed, that would tend to indicate a mismatch problem. Hopefully we can deal with that.

I hope you can tell which DIMMs belong to each set. G.SKILL usually has sequential serial numbers on memory kits, so you should be able to sort them out.

Your main re-configuration is to use DIMMs from the same kit in a channel. Whether or not it makes a difference in the sequence of DIMMs kits in each channel (ie Kit1 Kit1 Kit2 Kit2 Kit2 Kit2 Kit1 Kit1) is unknown. Or if you can use a mix of two kits regardless of their location.

Personally, I've had good luck using mixed kits of DDR4 memory, from a different manufacture. That is only one instance of that working for me, so cannot be taken as an overall trend IMO. You may get lucky, or not. You seem to not be lucky so far.

Intel guarantees your CPU to work with DDR4 memory at speeds up to 2133. So your 2400 memory is considered a memory OC. While DDR4 memory tends to OC well in general, the more channels being used and larger capacities of memory cause the OC capability to diminish quickly.

Suggestions for the memory error issue:

1. Reconfigure DIMMs as above.
2. Set memory speed to 2133.
3. Check for any difference between the memory voltage set in the UEFI, and the actual value shown in the HW Monitor screen. Usually the actual voltage is higher than the option setting.
   
4. You'll want to increase the DRAM voltage when using eight DIMMs. If spec is 1.2V, use 1.3V+. You can always reduce the voltage once the errors disappear, hunting for the optimal level.
5. Besides DRAM voltage, you'll need to increase VCCSA (System Agent) voltage, and VCCIO voltage. Again you can over-shoot with the values and reduce them if the errors disappear.
6. Keep the memory timings and other settings at Auto until you are happy with the memory performance. Then you can attempt to set the timings, etc, to better values, if possible.
7. Only try to increase memory speed, or use the XMP profile once your memory is working well.
8. This is an important change in the memory settings, and should be done and kept that way while doing all of the above: Find a memory option called MRC Fast Boot, normally set to Enabled. Change it to Disabled, which will cause more "memory training" to occur. This can be a big help. You may need to keep that option Disabled. It slows down POST time, but is a minor trade off IMO. If you can't find that option, look for anything that has "training" in the name, and set it to enable training.
   

This is all a fair amount of work and will take time. You may find you are unable to mix the two kits of memory. G.SKILL is usually good about accommodating their customers, you may be able to get a fully matched set for a little more than you spent now.

Let us know what happens.