X99 (Taichi) - only seeing 48 of 64GB installed

New memory arrived today. I plugged it into the Taichi and it still only recognized 48 of 64 GB. I've decided to return the motherboard and replace it with an MSI X99A Tomahawk which has worked out of the box.

I'll assume it was a defect with my motherboard and not all Taichi motherboards.

For the record, I tried to send in for technical support through the ASRock website and I never had a reply.

Thanks for the help, I really appreciate that time that other users have put into the community here.

It's always been the D1 slot. the slots are A1 B1 C1 D1 and A2 B2 C2 D2. I'm populating A1 through D1. D1 intermittently recognizes the memory. Always sees it in System browser, but only intermittently shows up in the BIOS and is recognized as memory. Voltage defaults to 1.2V when in DDR2400 model.

It seems I get one boot right after CMOS reset where all 4 DIMMs show up, then a crash / freeze and on reboot only A1 through C1 show up as memory.

Even if I shuffle the memory into different slots, same pattern of events.

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Here are the order of events from last night:

Last night I reset the CMOS. Went into BIOS, turned off MRC Fast Boot, Turned on Memory test.

All 64GB showed up in BIOS and Windows. (I declared victory!)

I then rebooted to BIOS, set the memory to the first XMP profile (DDR3000). Wouldn't boot.

Reset CMOS again. Set 2 memory settings in BIOS. So back to DDR2400. All 64GB shows up.

Booted from USB and ran memtestx86 on 64GB of RAM. Froze.

Rebooted. Booted from USB and ran memtestx86 again - but only on 48GB of RAM.

Went to a completely vanilla BIOS (fresh off the "plug out, CMOS clear button pressed") and set those two advanced memory settings suggested by parsec (MRC fast boot disabled, memory test enabled).

It's super unstable. Freezes up in windows with no stress on the machine.

I ran memtest86 and it froze up. Next boot, only 48GB. Did the complete CMOS reset, still only 48GB.

So I assume this indicates either the RAM of the D1 DIMM slot are bad. Still don't know how to get to the bottom of it.

Is there a better set of RAM I should buy? If I don't care about overclocking but want 64GB and a stable machine, what would you buy?

I discovered something about this model of memory that I will discuss later, but first...

Have you run the memory at stock/Auto speed, which is 2400? If not, or if you have and are trying to use it at 3000, you need to get all of it running at its stock speed, 2400. You need to see if the CPU/memory controller, memory, and board together as a system can work with your memory at its stock speed. If it can't then something is not right and you'll need to diagnose it from there. If all your memory works fine at it stock 2400 speed, then you can move on from there to a higher memory speed.

FYI, all X99 HEDT processors like yours have their memory controller, which is part of the CPU itself, rated up to a speed of 2400. Speeds above 2400 are a memory over clock, and at best may need some work to achieve, and at worst may never be reached.

That means put all four DIMMs in the '1' slots only, A1, B1, C1, and D1. Be sure to use those slots, which are the closest ones to the CPU socket, in each of the four channels.

Then clear the UEFI/BIOS, which you can easily do using the CLR CMOS button on the board's IO panel. You must have the PSU off and unplugged from AC power when you use the CLR CMOS button. DO NOT skip clearing the UEFI/BIOS step, you MUST do this if you are serious about solving the problem.

When you clear the UEFI/BIOS, all the options will be reset to their default values. We want that for the memory, but if you have any other necessary settings, like RAID for the SATA mode (if you use it), you'll need to reset those again. That's normal after clearing the UEFI/BIOS.

It looks like from you pictures that you are using the EZ Mode of the UEFI/BIOS. You need to use the Advanced screens, so do that. There is more than one reason for this.

I want you to set an option only available in the Advanced UEFI screens, the DRAM Configuration screen, found in the OC Tweaker screen. In the DRAM Configuration screen, way down at the bottom (scroll down) find the MRC Fast Boot option. Set it to Disabled.

Below that option, find the Memory Test option, and set it to Enabled. Setting these two options will cause what is called "Memory Training" to occur, which helps when using large amounts of memory as you are.

You should also check the DRAM Voltage option, in the OC Tweaker, Voltage Configuration screen. That should be set to at least 1.2V, when the memory is at 2400 speed.

Question for you, have you installed Windows yet on this PC? Or are you simply using the UEFI/BIOS to look at the memory, etc?

As I alluded to at the beginning of my post, a review of this memory I found noted that when setting it to a speed of 3000 with the XMP2 profile, the XMP2 profile sets the BCLK to 125MHz, from the standard 100MHz. That change of the BCLK speed also affects the CPU speed, and causes a CPU over clock. For the standard 3.4GHz base speed of your CPU, that BCLK speed results in a CPU speed of 4.250GHz, and standard Turbo speed of 4.5GHz. That will happen when using one DIMM, or all four at the XMP2 speed of 3000.

http://www.hardwaresecrets.com/kingston-hyperx-predator-ddr4-3000-64-gib-memory-kit-review/4/

Which is why I'm wondering if you actually can run Windows at a CPU OC of that speed. Or was the review done with an earlier version of your memory, which no longer sets the BCLK to 125MHz. You need to verify if that happens or not. The BCLK frequency will be shown in the main OC Tweaker screen, and in the DRAM Configuration screen.

I've noticed when using the System Browser tool, it can take a while before all the memory is detected after the tool is started. You may even see "Detecting" when you hover the mouse pointer over the memory slots. Yes, a DIMM will appear in red when the mouse pointer is over that DIMM, that is not abnormal.

Odd D1 shows highlighted in Red in that System Browser pic.

IIRC it should show as Yellow like the other one.



Lemme as parsec here. He has an X99.