I have recently upgraded my homeserver to Lenovo M90S Gen4 SFF with i5-13600.It has a Q670 chipset. I ordered it with 16 GB of RAM and it came with a Samsung DDR5 UDIMM module with an advertised speed if 5600MT.In the bios hardware summary I could see this module working at 4400MT(assuming its chipset limit) Then I got a 64GB DDR5 kit of Patriot viper of advertised speed of 5600 MT. After installing them, I am only getting 2000MT speed in the BIOS. Unfortunately, there are no option to control the RAM configuration in the BIOS of Lenovo M90S. Is there a way by which I get at least 4400MTs from all 80GB RAM? If not what is the better tradeoff? 64GB at 4400MT or 80GB at 2000MT? I will be using this machine as Proxmox node.

  • computix@alien.topB
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    1 year ago

    You can’t throw enthusiast grade RAM that needs XMP into a name brand machine.

    Also don’t mix RAM if you want stability. You need to use modules that are exactly the same, down to the PCB layout and chip type if you want a supported 100% guaranteed stable configuration.

    To get the best performance from this machine you need to get RAM with a JEDEC profile for the speed you want.

    Also, in this datasheet it says the RAM will run at up to 4400 MT/s, very likely this is with only two single rank modules, maybe with two dual rank modules (the CPU supports this, but the machine may have thermal limitations). With 4 modules up to DDR5-4000 (4x SR) or DDR5-3600 (4x DR) is supported by the CPU. The machine may limit RAM speed below what the CPU supports because of thermal limitations in a tiny SFF housing. DDR5 gives off a lot of heat.

    • Aware-Data8635@alien.topOPB
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      1 year ago

      Hi, Thanks for your guidance. The patriot kit datasheetpatriot datasheeet that says base frequency is 4800MT. Is this the JEDEC profile? When I remove the samsung stick, the patriot sticks are reporting 4400 MT in bios. Also, I would still be ok if I can manage 4000MT or even 3600MT, but what I am currently getting is 2000MT which is a little disappointing. Can I still attempt that?

      • computix@alien.topB
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        1 year ago

        Yes, 4800 is the JEDEC profile, so it should be good for 4400 there.

        Like I wrote, don’t mix (DDR4 and DDR5) RAM, it won’t work right. It’s possible the BIOS has a safe guard that sets the RAM to 2000 MT/s if it sees mixed RAM.

          • computix@alien.topB
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            1 year ago

            The Samsung module is very different. I wouldn’t run such a mixture, I’ve seen too many problems with mixed RAM on here, but of course you’re always free to do your own thing.