Intel Core Ultra 285K, G.Skill CUDIMM 8800MT/s and Asus Z890 Extreme - no 8800 speed....even 8400 :(

[marko22]

Hello,

My issue began when I upgraded from an i9-10900K to an Intel Core Ultra 285K, along with an ASUS Z890 Extreme motherboard. In the five years I used the previous platform, I never experienced this many errors.

I’m unable to stabilize memory on this new motherboard. I initially used Corsair CUDIMM 8000MT/s 2x24GB modules, which I later discovered are not on the QVL list. So, I replaced them with a G.Skill 2x24GB 8800MT/s kit, which is officially listed on the QVL.

However, despite this theoretical compatibility, the system won’t boot stably with either XMP I or XMP II enabled. In both cases, I get critical system errors such as “MEMORY_MANAGEMENT” and “Kernel Mode Heap Corruption.” The BIOS is fully updated (version 1901).

I don’t believe the memory itself is the issue, especially since it's officially certified as compatible. I’m starting to wonder if this could be due to a faulty motherboard or CPU, or whether the CPU simply struggles to handle such high frequencies. I understand these frequencies exceed Intel’s official specifications, but considering motherboard and memory manufacturers—as well as Intel—actively promote such performance using XMP profiles, it should, in principle, be stable.

In this context, would this kind of failure be considered a valid reason for a warranty claim?

[JeanetteC_Intel]

Hello marko22,

Thank you for reaching out to Intel Communities.

I appreciate the detailed information you've provided about the issues with your new setup.

To better understand the root of the problem, I would like to gather more details about your system. Please confirm if this is the actual device you are using. Additionally, sharing your system configuration will help me provide a more accurate solution. You can do this by downloading the Intel® System Support Utility for Windows*. Once downloaded, launch SSU.exe.

• Scan: Check the box Everything.
• Click Scan.
• Review: When finished scanning, click Next.
• Click Save. *Attach the SSU log file as you reply.

I look forward to your response.

Best regards,

JeanetteC.

Intel Customer Support Technician

[marko22]

Hello @JeanetteC_Intel 

Thank you, Jeanette, for your response.
Please find attached the SSU diagnostic scan as requested.

I would like to highlight that I have over 30 years of experience with PC hardware, both on a professional and enthusiast level. For the past five years, I used an Intel Core i9-10900K with the ASUS Z490 Extreme motherboard without a single issue—no BSODs, system instability, or hardware faults.

Since upgrading to the current platform in January (Intel Core Ultra 285K, ASUS Z890 Extreme, and G.Skill DDR5 8800MT/s 2x24GB), I have been experiencing persistent system instability and memory-related errors, despite all components being high-end and seemingly compatible.

As part of my troubleshooting, I reviewed related topics on the ASUS ROG forums and came across a discussion that aligns closely with my experience. A user there suggests the root cause may be the integrated memory controller (IMC) of the CPU itself:
https://rog-forum.asus.com/t5/intel-800-series/g-skill-xmp-8800-mhz-problem/td-p/1091735

To validate this theory, I performed memory stress tests using OCCT across a range of frequencies: 8800MT/s, 8600MT/s, 8400MT/s, and 8200MT/s. Each configuration eventually produced errors on physical CPU cores during load, indicating IMC-related instability under high-frequency DDR5 operation.

It is important to note that the system does not crash immediately upon applying XMP. Errors surface after extended stress testing, suggesting marginal IMC stability or insufficient tolerance at higher memory speeds. The behavior is consistent regardless of BIOS version or memory voltage adjustments within safe limits.

At the time of writing, the memory is running at 8000MT/s using XMP I. However, long-term stability at this setting is still uncertain.

Given the ongoing issues and the premium nature of this hardware, I would appreciate further analysis or escalation of this case. If the CPU's IMC is not capable of handling the advertised memory speeds—even with supported modules—this should be clearly communicated or addressed via BIOS microcode updates or revised IMC specifications.

Please let me know if any additional diagnostic data or logs are required.

Best regards,

Mariusz M.

[JeanetteC_Intel]

Hello marko22,

Thank you for sharing the SSU diagnostic scan and detailing your experience with the current platform. Your extensive expertise in PC hardware provides valuable context to the situation.

Considering the high-end nature of your hardware and the ongoing challenges you're experiencing, I recognize your concern and the necessity for a solution. I will escalate this issue for further examination to ascertain whether the IMC's performance at the advertised memory speeds is the underlying problem.

I will inform you if any additional diagnostic data or logs are needed and will provide an update as soon as it becomes available.

Best regards

JeanetteC.

Intel Customer Support Technician

[JeanetteC_Intel]

Hello marko22,

Upon further checking, the issue appears to be related to the processor. To further diagnose the problem, kindly follow these steps:

1. Conduct an IPDT test to assess the processor's health and share the results with us.
2. Run an XTU stress test and provide the results.
3. If possible, kindly perform a swap test. This involves placing the processor in a different motherboard or vice versa and swapping some components to help isolate the issue. *Please share the components that will be used for the swap test.

I look forward to your response.

Best regards

JeanetteC.

Intel Customer Support Technician

[marko22]

Hello Jeanette,

I finally found some time to run the tests. So here’s what I’ve got: The IPDT processor test completed successfully with memory set to 8000MT/s. XMP I profile in BIOS, all other settings left at default. Up to 8400MT/s, the XTU test passes all four options without issues.
At 8600MT/s, the test ran for about 7 minutes on the AVX2 option, and then the computer rebooted. A memory management issue. Screenshot from the WhoCrashed app is below. Previously I had a System_Service_Exception error.

Well… if I have to stay at 8000MT/s, I’ll just have to live with it.
Still, it bothers me. Overall, I feel like the system is strangely sluggish. Recently I built a PC using my old processor and a Gigabyte motherboard, along with my RTX 3090—and subjectively, it seems to run better than my current platform. I have no idea what to do about this.

Regarding testing the CPU and memory on another motherboard... unfortunately, I don't have that option.

Best regards.

Mariusz M.

[JeanetteC_Intel]

Hello marko22,

Thank you for providing the test results and the additional details I requested. Although the test passed, the performance remains sluggish, and swap tests aren't possible. I will continue to investigate this issue internally and will update you as soon as more information is available.

Best regards

JeanetteC.

Intel Customer Support Technician

[marko22]

Hello Jeanette,

The CPU passes the IPDT test successfully at every memory setting — even at 8800MT/s. The problem appears during tests involving both memory and XTU. The last system error occurred with settings at 8000MT/s, so even at that speed, I can't be certain the system is functioning correctly.

I wanted to have the processor and memory tested at a major computer store here in Belgium. Unfortunately, they declined and referred me to the stores where I bought the components. The issue is that I bought the processor and motherboard in one store and the memory in another.

I’d like to at least eliminate the memory from this equation. Out of the three memory kits I’ve tried, I find it hard to believe that faulty memory is the problem.

I’d be grateful for any advice or suggestions.

Best regards

Mariusz M.

[JeanetteC_Intel]

Hello marko22,

Intel does not guarantee overclocking results, including those on the XMP Certified list. Overclocking margins depend on the combined conditions of the motherboard, module, DRAM, CPU, and the system's thermal and voltage tolerances. Not every unit or system will achieve successful overclocking or produce the same results. The module indicates a "Tested Speed (Up To) 8800MT/s," but in this instance, you were reaching an unstable environment at 8000 MT/s. 

Therefore, we recommend that consulting the specific motherboard QVL list of tested memory and reach out to your motherboard vendor with any questions. 

When examining the F5-8800C4255H24GX2-TZ5CK and checking the QVL section, your motherboard is not listed, only the ROG MAXIMUS Z890 APEX. Additionally, the Intel® XMP 3.0 Memory for Intel® Core™ Processors Datasheet does not include this combination. For more information, you can refer to the ARL-S Overclocking tab, which provides a list of memory modules.

I hope this information helps.

Best regards,

JeanetteC.

Intel® Customer Support Technician

[marko22]

Hello Jeanette,

Jeanette… I’m fully aware that Intel doesn’t guarantee overclocking results. No one can guarantee that. However, everyone buys certain hardware believing it will work as labeled. I understand these are nuances. There are always two outcomes: either it works, or it doesn’t. Unfortunately, I’m currently out of luck.

As for my memory modules… the strange thing is that they are on Asus’s QVL list. But on the G.Skill website, this motherboard isn’t listed—only the Apex is. Oh well… this has taught me a lesson for the future: to analyze every detail even more carefully when it comes to hardware.

And by the way… all these lists are practically worthless, since there’s no real guarantee of proper operation. So what does such a certification even mean? Practically nothing. It’s just a marketing incentive for the buyer. Then you end up struggling because you didn’t read the fine print.

Thank you for your interest and help.

Best regards

Mariusz M.

[JeanetteC_Intel]

Hello marko22,

We value the overclocking community and offer a number of great features that enhance their ability to increase processor frequency and performance. However, even as we work with the community to push the boundaries of what’s possible for those desiring additional performance, we want to be transparent that there is always a level of risk involved.

Overclocking is comprised of many different variables and each individual has their own methodology, all of which carry an element of risk and lie outside the parameters that Intel tests and validates. 

Intel ensures that the platform tools exist and function for those that decide to operate beyond Intel’s validated and warranted configuration.

Regarding the XMP configuration the motherboard, it would still be best to consult your motherboard's support team for further assistance.

Sincerely,

JeanetteC.

Intel Customer Support Technician