Can I differentiate different RDIMM models electronically?

Autumn

5/18/23, 8:59 AM

I bought 128GB of Hynix RDIMMs off ebay. The (slightly lifted) label indicates that they are (as advertised) Hynix model HMT84GR7AMR4A-H9, which is 1333 MHz registered RAM.

However, lswh -C memory returns

description: DIMM DDR3 1066 MHz (0.9 ns)
product: HMT84GR7AMR4A
vendor: Hynix Semiconducto

and dmidecode -t 17 gives me Speed: 1066 MT/s.

And indeed, there exists a Hynix submodel of part HMT84GR7AMR4A (with the -G7 suffix) which is 1066 MHz. It occurs to me that maybe the vendor switched labels.

I'm not confident though. If my motherboard guessed the RAM clock wrong (there is no setting), would lshw and dmidecode be reporting a speed of 1066? Or are those hardcoded strings coming back from the DIMM?

0 + 0

hardware

ram

dmidecode

lshw

matigo

5/18/23, 12:57 PM

What is the brand and model of the motherboard that these RAM sticks are installed in? Are you mixing 1333MHz and 10066MHz models?

Autumn

5/18/23, 4:35 PM

It's a Lenovo Thinkstation S30 motherboard, one of the earlier versions, probably type 0567. All of the DIMM labels indicate H9, but I haven't booted with them singly to check the `dmidecode` strings.

matigo

5/18/23, 10:33 PM

Based on [the promotional material for that machine](https://www.lenovo.com/medias/thinkstation-s30-ds.pdf?context=bWFzdGVyfHJvb3R8MjQ2Mjc0MnxhcHBsaWNhdGlvbi9wZGZ8aDc3L2g3NC85NDQyOTk3OTI3OTY2LnBkZnw5MTU3NmIyNmE4MGY0NWIzMWU2MDg2YjEzMmMyYjI3MDk2ZWU3MTVmNmE2OTdhNDRmNjgxYjhkN2IwZTljYWFi), it supports RAM with a bus speed of 1600MHz. This should allow your 1333MHz sticks to move at 1333MHz so long as it’s not being mixed with a 1066MHz stick. The hardware will always try to accommodate the slowest component

Autumn

5/19/23, 1:19 AM

Thanks! Tested individual sticks, they all come up as 1066. I'm going to try to find someone else in town with a DDR3 server to make sure it's not my mobo before I start a dispute with the vendor. :-(

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Can I differentiate different RDIMM models electronically?

TH: ฉันสามารถแยกความแตกต่างของรุ่น RDIMM ทางอิเล็กทรอนิกส์ได้หรือไม่

RO: Pot diferenția electronic diferite modele RDIMM?

RU: Могу ли я различать разные модели RDIMM в электронном виде?

VI: Tôi có thể phân biệt các mô hình RDIMM khác nhau bằng điện tử không?

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