Question Computer Keeps Overriding XMP Profile

Cathaldus

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May 24, 2015
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Hi there,

My motherboard is ASROCK B450M Pro and the manual advises that it supports quad channel.

I used to be able to run memory at 3200 GHZ with 2 sticks with the XMP Profile, however, now after adding 2 of the same exact ram sticks to have 32GB of RAM at 3200MHz it keeps resetting to 2133MHz.

Any ideas why this is happening?
 
here found original ram support for 2nd gen ryzen



that post is old, agesa updates got some ram improvements since then, but i wouldnt expect running it higher then 2666
 
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keith12

Glorious
here found original ram support for 2nd gen ryzen



that post is old, agesa updates got some ram improvements since then, but i wouldnt expect running it higher then 2666
Exactly, CPU only supports 2666mhz on 4 DIMMs. Whilst some chips can go higher, it's a bit of a lottery. (IMC silicon lottery) Supported speeds are all you are guaranteed.

Ideally you want a 4 x matched kit. Even mixing DIMMs which are identical in all specs with those from another kit with the same spec, there's no guarantee.
 

keith12

Glorious

Karadjgne

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Zen, Zen+, Zen2 cpus do Not like 4 sticks. At all. It's a memory controller limitation to do with the infinity fabric.

Zen+ cpus are pretty much good to get 2933MHz with 4x sticks, very few get the full 3200MHz and that normally requires not only ram voltage tweaking, as high as 1.4v, but also setting SOC voltage to 1.2v maximum as well as possibly relaxing some timings.

Out of those capable of stability at 3200MHz with 4x sticks on Zen+, almost all are Samsung B-die OEM, very rarely Micron D-die, and SkHynix is outta luck afaik.
 
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keith12

Glorious
The interesting thing now is I just got it to get to 2800MHz after a reset.
It's possible the new bios gave more stability with SOC voltage and maybe why it's working at 2800 as opposed to the 2666 max supported for 4 DIMMs.

Well, that's good! It's another strap higher than before, so will still bring some benefit over 2666mhz, even though it's not that much of a difference in real terms.
 

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