Question Major problems with memory stability?

Sep 20, 2021
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For a while I had a brand new NZXT PC built by NZXT (this is not redundant as they also sell kits). Early in the life of the PC (within first few days), I had a BSOD, which with tech support was fixed by updating the BIOS.

One thing that I did not take note of (because I did not know it existed) was to check memory timings. I had assumed this was automatic. I have no idea what the original timings were.

However, I do know from my hefty invoice that I have Teamgroup's Xtreem 2x16GB 4000Mhz DDR4 RAM. I also UPGRADED to 64GB of RAM by adding 2 more 16GB banks of the EXACT same model RAM.

What I did not anticipate was that if there were any adjustments ever made to the RAM, it would have been gone when I upgraded the BIOS. So without any knowledge of what went before, when I learned of XMP profiles, I went into BIOS and sure enough, XMP was disabled, and speed was 2400Mhz. Okay, no biggie, its an Aorus 590 motherboard, so even easy mode you can one-click enable XMP, which I did, which changed the RAM speed to 4000Mhz and instantly crashed the PC on next reboot. Tried a few more times, crashing each time, then gave up, entered the BIOS and set it to 3900Mhz. No crash and I went into Win 11 to run CPU-Z.

CPU-Z spat back these numbers:
MEMORY TAB
Uncore freq: 4000Mhz
DRAM freq: 1900Mhz
SPEED TAB
Max bandwidth: DDR4-4000
A bunch of JEDEC numbers which I can provide if necessary but they seem unrelated.

My questions:
a) Why did the PC crash at BIOS setting 4000Mhz, the rated speed of the RAM, but not at BIOS setting 3900Mhz, and did I really solve any problem or just kicked it down the road? Was there a better way to handle this?
d) What is CPU-Z saying? Why is my DRAM speed half of my uncore speed? What number should I use?

Thanks!
 
Your PC crashed for these probable reason's

4000Mhz OC RAM is beyond JEDEC standard frequency and there will be no XMP profile for easy Overclocking. Your OC was unstable and Bios could not find a workable SPD (Serial Presence Detect) so it shut down. 4000Mhz and 64GB would put quite a strain on the IMC (Integrated Memory Controller)
List your CPU?
What is your need for 64GB?
Have you Mixed/Combined kits? List the P/N of each kit.

With OC RAM there is no guarantee you will achieve the rated frequency as it depends on the strength of the IMC (Integrated Memory controller) on your chip.

DDR stands for Double Data Rate and the 4 indicates the forth standard of DDR. RAMs actual clock speed is half of it's effective data rate so DDR4 3000 has a clock speed of 1500Mhz, DDR4 3200 has a clock speed of 1600Mhz.
Your Timings table in CPUZ shows this.

With OC RAM you have to tweak Bios Timings and Dram Voltage if there is no profile for easy Overclocking. Selection of OC RAM is important and best is to determine the size you need at a frequency the MB and CPU support. What you choose should be listed on the MB QVL so you know they are tested and known to work. The kit should be a single kit as mixing kits (even with exactly the same specs) is a NO NO due to minor variations in Latency/Density and is a common cause of mismatch.

Aorus Z590 is a decent MB and supports up to 5400Mhz using 11th gen CPU. whilst 10th gen supports up to 2933Mhz.
List your Processor?
 
Last edited:
Sep 20, 2021
62
1
35
0
Your PC crashed for these probable reason's

4000Mhz OC RAM is beyond JEDEC standard frequency and there will be no XMP profile for easy Overclocking. Your OC was unstable and Bios could not find a workable SPD so it shut down. 4000Mhz and 64GB would put quite a strain on the IMC (Integrated Memory Controller)
List your CPU?
>>>i9-11900
What is your need for 64GB?
>>>I started with 2x16GB of RAM but soon discovered that my board was daisy chain topology (this is a pre-built PC by NZXT, so I did not choose components). Furthermore, the RAM were single rank ram in two slots. Therefore, I figured that getting antoher 2x16GB would kill 2 birds with one stone, make it dual rank equivalent and also and just that bit more buffer for the rare occasions I do video editing and perhaps some improvement in MSFS. But mostly for the dual rank reason.
Have you Mixed/Combined kits? List the P/N of each kit.
>>>They are all four identical RAM, Teamgroup T-Force Xtreem 16GB 4000mhz.
With OC RAM there is no guarantee you will achieve the rated frequency as it depends on the strength of the IMC (Integrated Memory controller) on your chip.

DDR stands for Double Data Rate and the 4 indicates the forth standard of DDR. RAMs actual clock speed is half of it's effective data rate so DDR4 3000 has a clock speed of 1500Mhz, DDR4 3200 has a clock speed of 1600Mhz.
Your Timings table in CPUZ shows this.

With OC RAM you have to tweak Bios Timings and Dram Voltage if there is no profile for easy Overclocking. Selection of OC RAM is important and best is to determine the size you need at a frequency the MB and CPU support. What you choose should be listed on the MB QVL so you know they are tested and known to work. The kit should be a single kit as mixing kits (even with exactly the same specs) is a NO NO due to minor variations in Latency/Density and is a common cause of mismatch.

Aorus Z590 is a decent MB and supports up to 5400Mhz using 11th gen CPU. whilst 10th gen supports up to 2933Mhz.
List your Processor?
 
Intel 11th gen i9-11900 officially supports up to 3200Mhz so you may have exceeded the limitations of the IMC and with 64Gb you would have stability issues.
Mixing kits as you have would exacerbate the situation and can result in unexplaind shutdowns or reboots.

Please List all RAM kits P/N or SKU.? which can be found on the modules or the box they came in. As I said, Even modules with exactly the same specs can mismatch if they are from differing kits and the reason DIMM modules are binned at the time of manufacture.
 

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