Niall’s virtual diary archives – Friday 27 September 2019

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Friday 27 September 2019: 12:34. I finally got in the replacement for that bad RAM stick as mentioned in my previous post about fitting 128Gb of RAM to my Threadripper rig, so I can at last report memory bandwidth.

As a reminder, I have fitted 8x M391A2K43BB1-CTD Samsung 16GB DDR4-2666 ECC UDIMM PC4-21300V-E Dual Rank x8 Module sticks in order to make 128Gb of RAM for my AMD Threadripper 2950X workstation with an Asrock X399 Taichi motherboard. These are not on the QVL list for any X399 motherboard, so it was a shot in the dark, but it turns out they work well, and overclock happily to DDR4-2933 @ 1.35v 16-15-15-36-50 by simply keying in the values in the BIOS. ECC automatically enables itself, it all “just works”.

My previous RAM was 32Gb of GSkill at 3200 16-18-18-38-56 from the QVL list. It saw 94,074 Mb/sec @ 67.7 ns.

New RAM sees 87,913 Mb/sec @ 71.2 ns. That’s 6.55% less bandwidth, and 5.2% worse latency. Not bad given the Threadripper’s internal fabric is running 6.4% slower. It won’t boot faster than 2933, can’t say if that’s the eight sticks fitted, or the RAM itself. Others on the internet think it is the eight sticks fitted, so no point in buying RAM faster than 2933 if you’re fitting eight sticks.

For the very cheap €564 ex VAT price I paid as compared to the alternatives for 128Gb of RAM, all of which cost a lot more, I’m very happy with my purchase. Very little loss of memory performance for oodles more capacity, and you get ECC!


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