[GTALUG] war story #2: buying RAM

[Nicholas Krause]

On 5/14/23 13:01, Lennart Sorensen via talk wrote:
> 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/
> 
XMP or a version  is on AMD. The problem your running into is CPUs these days default to a certain Ram Speed. I'm not sure of what gen your on for the Thinkpad but googling default memory speed of gen X, where X is your gen should resolve that issue. If you need to go helper than you need XMP or the AMD version to go beyond the default speed. For sure,3200 is beyond that for memory with current gen.


Nick