[SOLVED] Trouble Enabling XMP

[DerrySellers]

Hello
My Specs:

• Mobo: ASUS Maximus XI Extreme
• CPU: i9-9900k
• GPU: RTX 2070
• PSU: Corsair AX1600i
• Cooling: Custom Waterloop
• RAM: Corsair Vengeance DDR4 4x8GB 4000Mhz 19-23-23-45 1.35v -> Gskill Trident Z DDR4 4x8Gb
  4000MHz 15-16-16-36 1.5v

So first thing, I'm an overclocking noob. I let AI Suite handle the CPU overclocking, but recently while tinkering with some settings I noticed my RAM (Corsair Vengeance DDR4 4x8GB 4000Mhz 19-23-23-45 1.35v) was running at 2133MHz. I did some research on RAM and learned about the timings and frequency and how they work. Then I fell into the XMP rabbit hole. I found out my RAM was not running at 4000MHz because XMP wasn't enabled in my bios. Easy enough fix I thought, but no. I went to my bios and enabled XMP 2, saved, and rebooted. On the reboot, the mobo flashed a bunch of codes rapidly while the screened remained black, and then it reboots itself. It did that again on the second reboot so I hit both the bios and CMOS reset buttons on the back of the mobo. Reboot again and everything is as it should be, but now I'm back to default settings and my RAM running at 2133MHz. I tried manually adjusting the voltage and timings in the bios to the above specifications and when that didn't work I adjusted them incrementally to see if it would post, but no dice.
From there I decide to run a MemTest. I didn't have any USB sticks lying around so I had to opt for Windows Memory Diagnostics Test at the moment. It runs the test and halfway through it said that hardware failure had been detected, it continued to run the test until about 3/4 of the way when it crashed. I get on new egg and order new RAM sticks (Gskill Trident Z DDR4 4x8Gb 4000MHz 15-16-16-36 1.5v).
Fast forward to today. They arrive. I install them, boot the computer, things are working fine. I downloaded Karhu RAM Test, let it run for 30 min using 24448mb and 16 threads. I got around 500% coverage and 0 error count. From there I shut down the PC, boot to BIOS, enable XMP 2, and this time in the middle of booting it throws a mobo code of 55 then BSOD's with error code 0x000000e. If I reset the BIOS back to default it works fine. I'm currently running a longer test using the same settings and as of this moment, its been running for 2 hours and 27 min with 2869% coverage and 0 error counts.
I'm now at the point where I don't think any more self research is gonna help me, and I need an experts advice. Any ideas? All help is very much appreciated. Cheers!

 

[mamasan2000]

Intel 9900k Max Ram Speed

The Intel website says the max supported ram speed for the I9 9900K is DDR4-2666. So i figured that getting anything above that speed would be pointless. Because the CPU would not be able to take advantage of the extra speed. But last night i watched this video from Linus where he used the I9 990...

linustechtips.com

I don't think a 9900k can handle 4000 Mhz RAM, not without tinkering at least. First I would try 3600 Mhz with tighter timings or just stick to what XMP gives you, just lower the clockspeed. There shouldn't be much point in going over 3600 Mhz. Comparison pic in the thread I linked.

 

[CompuTronix]

DerrySellers,

On behalf of Tom's Moderator Team, welcome aboard!

High-end memory kits with fast XMP Profiles don't always work as advertised, as it depends on variables such as the quality (silicon lottery) of your particular processor's IMC (Integrated Memory Controller) as well as motherboard features and BIOS capabilities. However, if you're willing to invest the time that's necessary for stability testing, you can still potentially achieve fast memory performance by calculating "True Latency" which is a basic and simple method to help you gauge memory performance so you can find and tweak your best frequency and timings using alternate settings.

For example, we built a 9900K for one of my Nephews that has a G.Skill kit similar to yours, which was 16 GB (2 x 8) Trident Z RGB DDR4 4000 16-16-16-36 @ 1.4V. But just as you've discovered, his 9900K wouldn't boot at the advertised XMP 4000 settings. Instead, by calculating the True Latency of different settings and testing those combinations, we were able to achieve a result which was very nearly as fast as XMP, by using the next-fastest stable frequency at the lowest stable timings. Let's explain:

Cheap and "sloppy" memory kits have a True Latency of around 10.0 to 12.5 nanoseconds (nS) or higher, whereas better kits have a True Latency approaching 8.0 nS, while the faster more expensive kits are 8.0 to 7.5 nS or even a bit less (lower is better).

True Latency = Time ÷ Frequency x Timing. Here's how to calculate True Latency, which is expressed in nanoseconds (nS):

Time = 1 second
Frequency = GHz in Single Data Rate, which is 1/2 DDR, so any DDR4 memory kit @ 3600 MHz is 1800 MHz (as reported in CPU-Z) or 1.8 GHz.
Timing = CL (Column Latency, also called Column Address Strobe or "CAS") which is the 1st value in the primary timing specs seen on the label of a memory module, such as 16-16-16-36-2T.

Where the DDR4 3600 kit calculates as:

Time = 1
Frequency = 1.8
Timing = 16

So: 1 ÷ 1.8 x 16 = 8.88 nS (True Latency)

Where the DDR4 4000 kit calculates as:

Time = 1
Frequency = 2
Timing = 16

So: 1 ÷ 2 x 16 = 8.00 nS (True Latency)

For my Nephew's 9900K, we settled on 3733 MHz (1/2 DDR @ 1.867 GHz) @ 15-15-15-35:

So: 1 ÷ 1.867 x 15 = 8.03 nS (True Latency)

Our frequency and timing combination (with a slight voltage increase to 1.41) has proven to be stable after multiple runs of MemTest, as well as in gaming and daily use. You might find that 3800 @ 15-15-15-35 might work for your memory kit, which would be:

1 ÷ 1.9 x 15 = 7.89 nS (True Latency)

However, with respect to voltage, Intel's specification for DDR4 is 1.35 +/- 0.5% which is 1.4175 volts, or about 1.42 volts. When you increase memory voltage, the voltage is being applied not only to the memory chips themselves, but also simultaneously to the CPU's IMC, which is located within the processor's silicon DIE. Too much voltage can potentially cause electromigration and degradation of the IMC, which can eventually lead to intermittent memory instabilities, crashes, BSODs and data corruption. This is equally true for CPU Core voltage (Vcore). So when overclocking and tweaking memory as well as your CPU, it's prudent to be both cautious and conservative about voltage. Moreover, always run a total system backup prior to tweaking your settings, since the process inevitably involves software crashes.

When choosing a memory kit, keep in mind that when you overclock your memory, you're simultaneously overclocking the CPU's IMC. Overclocking results are typically better with 2 slots populated rather than all 4 slots, as it reduces the workload on the IMC. So at the same timings, a 32 GB 2 x 16 kit may overclock better than a 32 GB 4 x 8 kit. Also, cooling is generally not an issue for memory modules, but if all 4 slots are populated, then the inner modules can't cool as well because there's no space for air to circulate between them.

Once again, welcome aboard!

CT

 

[inc0wnage]

Hello,

I have the same concern: I purchased high-end RAM (4166 MHz CL16) but I cannot enable XMP (Windows won't boot). It will start with 3200 MHz. I managed to make it start with 3333 MHz and play PUBG but I cannot reproduce.

RAM: G.Skill Trident Z Royal 2x16GB DDR4 4166 MHz CL16 - Gold
Motherboard: Asus Prime Z390-P
CPU: i7 9700k
Cooling: Corsair Hydro Series H150i PRO

Now I understand that it's normal that I cannot fully benefit from this high-end RAM, but 3200 MHz only is a bit disappointing. Do you think that's normal, given the MB/CPU I have?

16/2133 gives 7.5 nS
12/1600 gives 7.5 nS
Does it mean I could expect to run CL12 with 3200 MHz and that would be the best I could hope for?

Thanks,

 

[mamasan2000]

Hello,

I have the same concern: I purchased high-end RAM (4166 MHz CL16) but I cannot enable XMP (Windows won't boot). It will start with 3200 MHz. I managed to make it start with 3333 MHz and play PUBG but I cannot reproduce.

RAM: G.Skill Trident Z Royal 2x16GB DDR4 4166 MHz CL16 - Gold
Motherboard: Asus Prime Z390-P
CPU: i7 9700k
Cooling: Corsair Hydro Series H150i PRO

Now I understand that it's normal that I cannot fully benefit from this high-end RAM, but 3200 MHz only is a bit disappointing. Do you think that's normal, given the MB/CPU I have?

16/2133 gives 7.5 nS
12/1600 gives 7.5 nS
Does it mean I could expect to run CL12 with 3200 MHz and that would be the best I could hope for?

Thanks,

Here is someone who got their 4133 @ 18-19-19 to run at 3800 Mhz @ 18-19-19
https://hwbot.org/submission/4808462_torresmon_y_cruncher___pi_2.5b_core_i7_9700k_2min_8sec_685ms
Probably silicon lottery, luck of the draw, how good your IMC is.
I'm guessing you paid a hefty premium for that RAM. Maybe return it and get a normal 3200 Mhz kit. Or you could play with the sticks you have. Who knows, maybe you can beat his score?

 

[HappyTrails]

Notice that when XMP enable my windows updates have a much higher fail rate. Have the 3600mhz dominator ram sticks and they ok but didn't buy the fast stuff. Can actually notice about 10% fps gains in certain titles difference 2133mhz vs 3600mhz. Also run ram that fast had twitchy system I thought was ram related but now I am thinking it was a bad gpu that I recently had to replace. Not expert here with ram but it fun to tweak speeds.

 

[inc0wnage]

Here is someone who got their 4133 @ 18-19-19 to run at 3800 Mhz @ 18-19-19
https://hwbot.org/submission/4808462_torresmon_y_cruncher___pi_2.5b_core_i7_9700k_2min_8sec_685ms
Probably silicon lottery, luck of the draw, how good your IMC is.
I'm guessing you paid a hefty premium for that RAM. Maybe return it and get a normal 3200 Mhz kit. Or you could play with the sticks you have. Who knows, maybe you can beat his score?

I'll try to play with the timings. Before I run the benchmark, what is a better configuration for the 4 primary timings? Their sum be minimized? Or the first timing, CL, to be minimized? Or something in between?
I'm able to play PUBG game with 14-19-19-39 (stock timings for 4266 MHz are 16-19-19-39).
With 12-18-18-39 I was able to boot but PUBG kept crashing.
I tried many other combinations, for instance with 13-15-15-33 Windows was able to boot (but I didn't try PUBG).

- edit -
Well, my DRAM voltage was not 1.5 V (which is the stock voltage for my RAM) and with 1.5 V, I am now able to go to 3733 MHz with 16-19-19-39.

 

[CompuTronix]

inc0wnage,

On behalf of Tom's Moderator Team, welcome aboard.

Be aware that you have violated our Forum Rules in your very first post; one of which is do not hijack another Member's Thread. I strongly suggest that you go back and re-read the Forum Rules, which are located in the "Sticky" Threads at the top of every Forum. Also, rather than just respond to the Title or first post of a Thread, please read the entire Thread before posting, as another Member may have already posted the most helpful answer.

If you're posting comments, such as above, which contain your own questions that don't provide answers for the original poster (OP), then please start your own Thread.

CT