PTJim

Ok, after four days straight without any glitches, I think I've finally solved this one. It's a $7 adapter! After changing out everything but the power supply (that was next on the list), it occurred to me to try removing this right-angle adapter I've had installed on my 24-pin motherboard power connector for many months to relieve cable-bend stresses and a cleaner appearance; it's been working perfectly with my i9-9900K configuration: https://smile.amazon.com/gp/product/B07NZ5GXNF It's just two connectors, soldered together; no electronics involved, but removing it eliminated the crashing and glitching immediately. So I went back and ordered this one at 4x the price of my original part, with capacitors to supposedly smooth out power delivery: https://smile.amazon.com/gp/product/B07HZ6B6R1 Absolutely beautifully-built, but installing it brought back the problems immediately - it crashed again in 30 minutes. After removing it and just connecting the PSU's cable directly to the mobo again, everything's been fine for four days. Again, these parts work PERFECTLY with the 9900K CPU and mobo; it's just the 12900K setup that crashes. Has nothing to do with mfgr or build quality of the adapter - two completely different ones both failed. So I think that's it; unless I can find a part that doesn't cause crashing, I'll just have to live with a stock cable connection. Three weeks of frustration, two mobos, two CPUs and three sets of DDR4 finally led to a very subtle cause I've never heard of before. I hope this information helps somebody, including Corsair tech support teams, in the future. Cheers and again, thanks for the assistance along the way!

I may have FINALLY solved this problem, but it's too soon to be sure, so I'll report back to confirm one way or the other. System has been up and running for 28 hours so far without a single glitch - while it was glitching, I could get anywhere from 10 minutes to about 15 hours before a crash. I want to let it run for 2-3 days or so before backing off the paranoia, expecting another blackout crash, and consider it fixed. If I confirm a fix this time, or even if I don't, I'll follow up on this; it's the least I can do to give back some knowledge in return for all the assistance to date. TEASER HINT: absolutely none of the other ideas or possible failed-parts suggestions seem to have been the issue. If this is the fix, it's one I've never, ever run across and is very subtle.

MSI Support responded to my ticket with suggestions to disable EIST and C-State in Advanced BIOS settings; watched a Linus TechTips video about that and got my hopes up a bit. Disabled both and she ran for about 30 minutes before failing again - the Event Log shows all the Kernel-Power Critical Errors when reboots happen, but otherwise no clues and I'm out of ideas except for the CPU swap in a few days. Frustrating......

Amazon is shipping me a replacement i9-12900K; I'm running out of things and ideas to try! With all the swapouts and reversions to previous mobo/CPU, I may have to order more thermal paste, too. As always, will report back so as to not let my legions of fans hanging.........

Well, that wasn't it - another crash/reboot with DDR4 voltage set to 1.35. I think my only remaining options to try (other than just giving up and reverting back to my i9-9900K configuration for good) are either to return the 12900K for a replacement (still think a defective CPU is unlikely) or return the MSI mobo for a different make/model - anybody have recommendations for a good, stable, solid mobo for the Z690 chipset? Sigh.

Just noticed something new: my MSI mobo sets the DRAM Voltage to 1.19V in both stock and OC modes and I discovered that TeamGroup specifies 1.35V - could that be the issue all along? Have had three reboot/resets this morning so far. I've set the mobo to Profile 1 overclock and manually changed DRAM Voltage to 1.35 - system is running (as you can see) and I'll see if it hangs in there, but was hoping for some thoughts on this voltage issue. Gracias.

Grrrrrr! Replacement mobo (same model) and new TeamGroup DDR4 (on MSI's compatibility list) and it's STILL rebooting! Was ok overnight but this morning just dumped out in the middle of email. The only thing I haven's swapped out is the 12900K CPU, but all tests I've run, including stress tests, have passed fine - could it still be a suspect part? Is there a fundamental problem with Z690 chipsets, MSI motherboards - getting desperate and very tired of rebuilding and reverting my system..... thanks.

Well, I'm back. Replacement mobo arrived and I've been on the hunt for compatible DDR4 that will fit under my Noctua cooler - man, this isn't easy! Most everything is NOT on the MSI QVL, but I finally realized I should try PC Parts Picker to help narrow things down. Also, low-profile sticks seem to be getting more rare as everybody moves to unicorn-barf RGB sticks that stick up much higher than the Corsair Vengeance, which I've loved for years in my 9900K build. So I have on order a pair of 2x32 3600 C18 from TeamGroup, having found nothing from Corsair that makes the MSI list (unless the eBay vendor who promised to check the version number has the v5.49 available) to have as a backup: TLZGD464G3600HC18JDC01 - which is on the QVL and at a very low price on Amazon at the moment. I plan to use the Corsair sticks because I like the brand, but so far have been out of luck trying to find v5.49, but maybe I'll get lucky. If not, supposedly the TeamGroup sticks have passed the compatibility test. Whew. For the sake of completeness for anybody still sticking with this boring thread, I'll update again, hopefully for the final/solved time. Thanks for the assist, gang.

Last night (at the very end of my 30-day return period) I arranged with Amazon to return my mobo and replace it with same model, which arrives Monday. After I shut this down, I plan to rebuild my i9-9900K older system in this case and rebuild with the replacement mobo early next week. With all the swapping/testing I've done with two sets of DDR4, it should have worked by now in some configuration. I'll come back to update if anybody's curious how it's going.

Crap, crashed again, with the newest DRAM, after about 25 minutes. All my usual apps/windows seemed just fine, then I tried to add TestMem5 to the mix - it crashed/rebooted right after double-clicking, even before that app loaded. So now I'm in the soup, not sure where to go from here. Bad mobo? Bad CPU? Both were the core of this upgrade last weekend; I'm just not sure how to debug this. Since the change was from LGA1151 to LGA1700 I don't have a different mobo or CPU to swap in for testing like the YouTubers have shelves and shelves of spare parts for their fiddling around. Is it possible my MSI mobo just doesn't like Corsair memory? Should I return the new sticks and try a different brand, or do a mobo or CPU swap first? One problem is that I got a good deal on both, the prices have moved back up about $200 total at the moment, and Amazon usually just does refunds, not replacements - that means I'd have to be absolutely sure I've got a dead part, because a return means I pay a significantly higher price on a replacement, which would be pretty annoying if the part turned out not to be the problem. Trying a different DRAM brand would be simpler but may not be the problem at all. Now I'm rambling; time to break away from this for a while to enjoy a Friday evening...... cheers, all.

Ok, new 2x32GB sticks arrived and are installed. BIOS was happy with them upon boot and everything started up normally, so I'm going to leave it running with my usual batch of apps/windows open and will see how stable it is - will probably let it sit overnight and run the bootable-USB MemTest86 tomorrow to give it a bit of a workout. If that goes well, then other stress/benchmark tests and maybe push it a bit in the BIOS to make sure it's stable. As always, fingers crossed................

Yes, you're correct the manual specifies 2/4 for one pair and slot 2 for a single. This specific memory model number is not on the MSI compatibility list, so I think either the list isn't comprehensive or this mobo just doesn't like this particular configuration. The 2x32 sticks on order are on the list (with a v5.49 note to the part number), so I hope I get that version and will give them a try before spending time with single sticks and alternate slots, for now. If the new sticks don't work (even though "on the list") I may take that approach to try to diagnose if it's a board failure. The fact that it can run normally for several hours tells me it's probably a timing glitch with this specific DRAM model number, but that's just a hunch. And I did open a ticket a few hours before starting this thread earlier in the week - haven't heard anything back yet so this has been far more beneficial. Will continue to update and continue to convey my gratitude for the assist.

The second pair of sticks just failed/rebooted after about 40 minutes. So I'm left with trying the two new 2x32 sticks when they arrive later on today, I suppose. Anybody know if it's worth inserting these older ones into slots 1/3 instead of 2/4, or does that not work for a 2-stick configuration? Thinking about trying to rule in/out a mobo problem, perhaps. I'm getting pretty adept and fast at pulling the GPU and one Noctua fan to swap these things......

It ran fine last night for a few hours, put it into sleep mode. Ran about 45 mins this morning, then failed again with another shutdown/reboot with just those two sticks in place. Since the new 2x32 sticks haven't arrived, I've swapped in the other pair of 2x16 into slots 2/4 to see if the problem might be a specific memory stick or if these just won't work in this mobo. Really hoping the mobo itself isn't the problem - that swapout is a much bigger deal and several days delay. Will continue to update here.

All four sticks are v5.49, see attached pic in the order most-recently installed. S/N's xxx330 and xxx331 are in slots 2/4 now. So far, so good; not sure how long it might take to evaluate if they're working stably because I haven't been able to figure out a way to make them fail - it's just a random thing taking a few minutes to several hours (and random number of apps/windows open, too) to trigger. There's no thermal issues at all BTW; CPU running in mid-20s mostly and my GPUs fans don't even come on at all unless I have a ton of charts or a VR game running - which isn't happening given the circumstances. The Noctua blower in the Torrent case is an amazing beast for those of us who don't like water looping around electronics but still appreciate a quiet system. More engineer-brain always worrying about the worst possible outcome..... Since I've got a bit of time, I may try both pairs each one at a time in both pairs of slots, just to prove to myself the hardware is more-or-less ok. My ME brain fails me again, though; I know slots 2/4 are the primary for using 2 sticks, but is it a problem just running in slots 1/3 or is that a no-go with current hardware designs? So I'll let these two sticks run at least overnight or until they ........ glitch 😬. Fingers crossed once more. If things are ok tomorrow noonish, I may as well swap them for the other pair to see how they fare. As mentioned way above, though, all four sticks have been 100% stable since installing in my i9-9900K platform 2.5 years ago, so I assume all are fine. If there's an unfixable problem running the four of them on this mobo, I'm assuming the new 2x32 sticks can handle that. I've probably got enough spare parts to just use the four older sticks to rebuild the 9900K to functioning status as a complete spare PC to satisfy my belt-and-suspenders backup approach to staying functional. Might have to buy a boot MVNE or SSD at most, I think. Thanks again.