[GTALUG] war story #2: buying RAM

[Lennart Sorensen]

On Fri, May 12, 2023 at 06:31:47PM -0400, D. Hugh Redelmeier via talk wrote:
> | From: D. Hugh Redelmeier via talk <talk at gtalug.org>
> 
> | So this is what I bought for $159.99:
> | <https://www.canadacomputers.com/product_info.php?cPath=24_311_1326&item_id=195989>
> 
> Surprise:  The ThinkCentre M75s gen 2 SFF seems this RAM as DDR-2400!  
> 
> Why???
> 
> Even though it is advertised as DDR-3200, when you read the 
> specifications, it will only run at 3200 under XMP.
> 
> <https://www.kingston.com/datasheets/KF432C16BBK2_64.pdf>
> 
>     FACTORY TIMING PARAMETERS
>     • Default (JEDEC): DDR4-2400 CL17-17-17 @ 1.2V
>     • XMP Profile #1: DDR4-3200 CL16-20-20 @ 1.35V
>     • XMP Profile #2: DDR4-3000 CL16-19-19 @ 1.35V
> 
> XMP is an Intel "standard" and cannot be used by AMD systems (like the
> M75s).
> 
> There are hacks for AMD.  For example Asus' DOCP.  But a business
> computer line like the ThinkCentre is unlikely to use that.
> 
> Now I have to return a second set of RAM.  Canada Computer might not
> be as accomodating as Amazon.
> 
> I wonder how one searcsh for "DDR-3200 RAM, no REALLY DDR-3200 RAM".

Good question.  I think one needs to somehow find ram that is 3200 and
1.2V explicitly.  The ones using XMP profiles seem to be 1.35V at
that speed.

This for example looks right:
https://www.amazon.ca/Crucial-2x16GB-Desktop-Memory-CT2K16G4DFRA32A/dp/B07ZLD6Q1G/

I guess you hit the same problem as this review:
https://www.amazon.com/review/R17NJ5JNV9HE4D/

-- 
Len Sorensen