Task Mgr says memory 2400; installed is 2666 and 3200

Lenovo ThinkCentre M920S (System One): Just today noticed that Task Manager says 2400, but I have 2 x 8GB 2666 and 2 x 8GB 3200 (that downclocks to 2666) RAM, and in Lenovo ThinkCentre UEFI, there's no XMP setting available, and no way to adjust the reported speed of memory. This machine has no speed problem whatsoever, but I'm curious about why I'm apparently operating at 2400 MHz, when all four of my memory sticks are higher than that. The evidence from CPU-Z and HWiNFO:

Does that 3200 downclock to 2666? There is no jedec profile for it at 1333 MHz. I kinda doubt it is that though.

It is not a good idea to mix RAM sets that are not the same in module manufacturer, ram chip manufacturer or speed. With mismatches the BIOS has to decide what to do and train it, which may be conservative - that might be the the only stable speed it could come up with.

When I bought it, the descriptions said

Crucial RAM 16GB Kit (2x8GB) DDR4 3200MHz CL22 (or 2933MHz or 2666MHz) Desktop Memory CT2K8G4DFRA32A​

• 3200MHz RAM can downclock to 2933MHz or 2666MHz if system specification only supports 2933MHz or 2666MHz.

Before I added the Crucial 16GB, I had just the 16GB of 2666 in slots 2 & 4, and Task Mgr said 2400 then, too. This isn't worrying me, because so far as I can tell, the system is not taking a performance hit because of the 2400 speed. I'm just curious.

I can't guess. Supposedly, with an I5-8400, the supported RAM frequency is 2666MHz. (With lesser CPUs, 2400.)

You have no RAM frequency adjustments in the BIOS settings?

A semi-random suggestion: switch around the RAM pairs in the DIMM slots. That should change which DIMM's SPD is read.

I'd be slightly worried about running mismatched RAM in a system that lacks a means of manually setting the RAM frequency and timings. However, if your system is stable at 2400MHz, you're doing well (IMHO). The practical difference between 2400 and 2666 is pretty small. (2400 is 90% of 2666.)

Absolutely stable, AFAIK. No problems.
Maybe I'll try just running the Crucial in slots 2 and 4, and see whether it shows up as 16GB @2666. Doesn't take long in these SFF boxes to make hardware changes. If that works, I might get another kit of the Crucial and see what happens.

I got a new Notebook Oct. '21 Win10 then upgraded to Win11 Pro. It came with 8GB 3200 and later I found a 4GB 2666 in my salvaged parts cabinet, just for s&g put it in the empty slot and have been running 12GB without issue for over a year now. Task Manager shows memory speed as 2400.

Berton said:

I got a new Notebook Oct. '21 Win10 then upgraded to Win11 Pro. It came with 8GB 3200 and later I found a 4GB 2666 in my salvaged parts cabinet, just for s&g put it in the empty slot and have been running 12GB without issue for over a year now. Task Manager shows memory speed as 2400.

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I think that suggests that the TM may not be reliable. But my BIOS shows 2400, too, and there's no way to change it in this machine. I'm going to try the 3200 by itself in 2 & 4, and see what TM and the BIOS have to say about that. The machine specs clearly say 2666 is OEM and standard, though.

I ran into the exact same issue when I got this Dell. It came with 2 sticks of Micron Ram at 2933. I ran Crucial scanner and bought 2 8gb of 3200. My speed dropped to 2400. I could run only the 2 sticks of Crucial ram and get 2933 OR the 2 sticks of Micron and get 2933 but could only get 2400 with all 4 mixed brand sticks installed. Dell sent me 2 more same 8 gb Micron ram sticks. With all Micron installed I get 2933.

@glasskuter Thank you for popping in with that. I think I'm going to try that.

Interestingly, on my System Two, CPU-Z correctly reports the RAM, and Task Manager says it's running at 2400 MHz.

Now the question is: Do I go with two more of the 2666 or two more of the 3200? The price difference is negligible. Advice, anyone? Oh, the 2666 currently is Gigastone, but CPU-Z calls it Samsung. The Crucial 3200 is actually Crucial.

Bigger, better, faster is always good as long as its affordable.

The best outcome in that scenario would be for the 3200 to downclock to 2666, and for TM and the BIOS to report that.

@Berton #7 and @glasskuter #9 showed me the guaranteed recipe for getting 2400 to show in the BIOS and TaskMan. Thanks to both for letting me benefit from their experience. I’m going with the 4 x 8 “Samsung” (Gigastone), and won’t post again on this issue unless something unexpected happens. Thanks to the rest of you, too.

I knew that for the pairs (1&3, 2&4) I should use same brand, same size, same speed, but I didn't know that the BIOS would not accept mixed brands (pair 1 brand X; pair 2 brand Y) at face value and would clock the whole set of four down. Now I know.

Wisewiz said:

@Berton #7 and @glasskuter #9 showed me the guaranteed recipe for getting 2400 to show in the BIOS and TaskMan. Thanks to both for letting me benefit from their experience. I’m going with the 4 x 8 “Samsung” (Gigastone), and won’t post again on this issue unless something unexpected happens. Thanks to the rest of you, too.

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If you are not experiencing any problem why bother getting new RAM sticks? The system is just confused because of the mixed RAM modules. I'll leave it if I were you.

@badrobot: Call it OCD. And tinkering with my computers is my primary entertainment these days. I try to spend as much time as possible doing things I enjoy and take satisfaction from. At my age, time is precious. Much more precious than money.

Wisewiz said:

@badrobot: Call it OCD. And tinkering with my computers is my primary entertainment these days. I try to spend as much time as possible doing things I enjoy and take satisfaction from. At my age, time is precious.

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If you have OCD why put different RAM modules in the first place? Hahaha. Nah, you don't need to answer that. Just don't look at the task manager and you will be fine. It's not like you will gain a performance boost.

Wisewiz said:

@glasskuter Thank you for popping in with that. I think I'm going to try that.

Interestingly, on my System Two, CPU-Z correctly reports the RAM, and Task Manager says it's running at 2400 MHz.
View attachment 76499

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It looks as your CPU-Z and task manager are reporting the same ?

These are mine,

@badrobot: Gotcha. Thanks.

Fabler2 said:

It looks as your CPU-Z and task manager are reporting the same ?

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Yep. I have two sticks of same brand, same size, same speed (2400) in there, so CPU-Z and TM and the BIOS agree. It's the other machine I was curious about, and Berton and glasskuter reported their experience with mixed brands and cleared my curiosity up.

BTW, I erred in #4 above, in saying that the TM-reported speed was 2400 with just the two sticks of same brand, same size, same speed (2666). This morning, I pulled the problem-causing "other-branded" sticks, and on reboot both CPU-Z and TM reported 2666. This afternoon, the two (more) sticks of same brand, same size, same speed will go in there, and I'm almost certain that CPU-Z, TM, and the BIOS will report all (32GB: 4 x 8) running at 2666.

@Wisewiz

In CPU-Z "only" the "Memory" tab, shows what speed the RAM is running at.
The SPD tab just shows the manufacturer's specs and the JEDEC timings tables.