F4-2666C15QR-16GRR XMP Profile Failing

[InfiniteClouds]

Hey there,

I'm running the F4-2666C15QR-16GRR kit on an ASUS X99 Pro with a Intel i7 5820K and when I try to run the XMP profile the system will not boot, and I get an Overclocking failed! error.

The kit is listed on the QVL for the motherboard. I have a module installed in A1, B1, D1, and C1, as suggested by the manual. Before returning the memory I wanted to make sure that there wasn't some mistake with the XMP profile.

Here are the changes it makes -

AI OC Tuner Auto -> XMP>
CPU STRAP -> Auto -> 125 mhz
BCLK 100-> 125
CPU Ratio Auto -> Sync All Cores

All 6 Cores Auto -> 29
Min CPU Cache Ratio Auto -> 24
Max CPU Cache Ratio Auto -> 24
Turbo Mode Enabled -> Disabled
Turbo Mode Enabled -> Disabled


I will most likely be running the memory at a lower speed because I want a higher CPU OC than your XMP profile has first I wanted to run MEMTEST with your stock XMP Profile to test the memory - however it will not even boot with it!

Thanks in advance for your assistance.

[emissary42]

Is your bios up to date?

Almost every X99 board out there got several updates to enhance memory compatibility and XMP support. That was somewhat expected however, since this is basically the first DDR4 architecture. Especially the ASUS models have progressed very nicely and some can now even use DDR4-3000/3200 at 1.00x strap.

[InfiniteClouds]

I'll have to check, I just bought the board a few weeks ago. I was surprised to see that the XMP was trying to raise the CPU speed at all. The profiles ratio of 29 coupled with th increased bclk attempts to bring the CPU to about 3600mhz, 300mhz over stock.. And none of these settings make any adjustments to voltages, either. If I drop ratio to 26 it will boot with the CPU at closest to stock as it can (3250) but I would've figured G.Skill tested their own profile.

I'll check my bios version.

[GSKILL TECH]

You can leave CPU Strap and BCLK to 100.

CPU Frequency can be overclocked with CPU Ratio alone.

Have you tried one installed with XMP enabled to see if that works?

[InfiniteClouds]

Sorry, I'm not sure what you mean by tried one installed with XMP?

Normally, whenever I OC my CPU I use BCLK 100 and just user the ratio/multipliers.

However, when I selected the XMP Profile to run the memory at the 2666mhz speed it made the changes listed in my original post, including raising the strap and BCLK to 125. When entered BIOS for the first time, this memory was running at 2133. Enabled the XMP profile is what brought it up to 2666 and I assumed it was done by the changes that the profile made to BIOS (including raising the BCLK).

You're saying to put the BCLK and strap to 100, but the XMP profile itself sets it to 125 - are you saying I should just not use XMP or am I misunderstanding the whole thing.

Thank you.

[emissary42]

You're saying to put the BCLK and strap to 100, but the XMP profile itself sets it to 125

Thats not quite right. The XMP does not force 1.25x. It is the motherboard that choses how to get DDR4-2666. Early X99 BIOSes often used the straps for higher memory clocks, since the manufacturers were still working on the dividers for higher memory ratios. For the most part this should already be fixed and esp ASUS made quite a progress with that.

Did you have time to check if the BIOS is up to date and/or update?

[InfiniteClouds]

I'm building this rig for a family member, right now it is over at their place so I'll be able to check it out tomorrow and I'll post an update.

Thanks very much for your help.

[InfiniteClouds]

OK soI've updated my bios but the XMP profile enabled still sets the strap and bclk to 125.. ?

Ok, so the XMP profile will give me a BSOD every time, even if I manually go into AI TWEAKER and and set the STRAP and BCLK to 100 (which then lowers the memory speed unless I alter the DRAM freq ratio). This also causes a 9C BSOD.


The ONLY way I can seem to prevent a BSOD is by loading DEFAULT BIOS settings, not enabling XMP but going into manual AI Tweaker and changing DRAM FREQUENCY setting to 2666hz. This automatically sets the CPU RATIO to SYNC ALL CORES which I must then set BACK to AUTO before saving and resetting. What's the deal?

Thanks again for your assistance.

[GSKILL TECH]

Manually input DRAM Frequency, timings, and voltage to see if that works better.