Question Why does my TUF B450M Plus Gaming motherboard always reset my DDR4 2666 mhz RAM to 2133 mhz ?

Computermaster04

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Aug 6, 2020
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Hello guys. I recently purchased new rams, ddr4 2666(4gb x 4 ). My motherboard always resets it to 2133mhz even though I choose 2666 in the OC section of the BIOS.
I also changed the Dram Voltage to 1.3000V but it always resets that to to 1.2V. I am wondering what is the cause of this problem? Please help.

Specs:
CPU: Ryzen 5 2600 (OC to 3.85ghz)
MOBO: Asus TUF B450M plus Gaming
Rams: 4x 4gb DDR4 2666 mhz
GPU: Rx 480 4GB stock
PSU: 650W
 
What BIOS Rev are you on? I'd stop at a revision that's pre-Ryzen 5000.

If you never have it would probably be good idea to reset CMOS settings.

Do you have an XMP profile, or DOCP as Asus calls it, enabled? If not you might try setting that instead of just setting memory clock speed.
 

Computermaster04

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Aug 6, 2020
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How do I know what rev is it? I tried changing via AI tweaker only. and there is no DOCP option in mobo. Actually if I install 3 rams, it will read as 2666 mhz. But when I put the last ram, it will beep 3x and wonr boot. So I tried resetting the cmos, but didnt work. When I changed the ram to 2133 l, it worked. Now, I cant change anything. It will just revert whatever changes I do with the ram.
 
How do I know what rev is it? I tried changing via AI tweaker only. and there is no DOCP option in mobo. Actually if I install 3 rams, it will read as 2666 mhz. But when I put the last ram, it will beep 3x and wonr boot. So I tried resetting the cmos, but didnt work. When I changed the ram to 2133 l, it worked. Now, I cant change anything. It will just revert whatever changes I do with the ram.
With the 4th DIMM it's trying to enable dual channel but dual channel is more demanding on memory controller with 4 DIMM's so it fails down to a default DDR4 clock speed. It's more difficult to get 4 DIMM's working at higher clocks and requires frequent CMOS resets, usually after any time it fails to train and restarts. When you reset CMOS always do it with both pulling the battery and shorting the reset pins.

One thing to do is try manually setting a DRAM voltage, I'd try 1.4V to start. You can try reducing it if that proves successful but DDR4 memory is safe up to 1.5V, although not over 1.4V in 24/7 use unless you have certain ram chips and you know it.

If you don't know your BIOS version you've probably never updated so it's a good idea to since updates quite specifically brought improved memory compatibility and stability. It should tell you BIOS version in the Advanced Mode/Favorites screen.

In the end, you may never achieve rated DIMM clock speed with 4 DIMM's unless you wade into the dark world of tweaking with memory timings. That's why most people just stay with a 2 DIMM arrangement in their systems.
 

Computermaster04

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Aug 6, 2020
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Oh so the rev is version. I did an update yesterday but no luck. So what you are sayin is to raise the dram voltage first? Then save and exit. After that, change it to 2666?
 

Computermaster04

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Aug 6, 2020
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It's version is 3202. It starts with rated clock,2133 but there is no way I can enable DOCP. I found it but there is no option for enabling DOCP. Only disable option. Haha.if I use 2 sticks only, it goes to its original clock, 2666 mhz.
 
It's version is 3202. It starts with rated clock,2133 but there is no way I can enable DOCP. I found it but there is no option for enabling DOCP. Only disable option...
That seems strange to me to have DOCP enabled by default. Although, when using 2600 rated memory, it's not uncommon to default to 2600 speed as it does the same with my Gigabyte motherboard and two different MSI boards. But they don't default to XMP enabled (XMP=DOCP with Asus) to do it.

That might be an undesired 'feature' of Asus boards...or then again maybe a sign something's wrong. Since it's always resetting it to 2133 when you put in 4 DIMM's, regardless of what you do, I tend to think it's the latter. It may be worth getting with Asus tech support about.
 
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