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Random/LFSR on P2

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  • I am curious how the integral ECC handshakes with the memory controller on ECC supporting platforms for error reporting.
    Historically, I had always initially disabled ECC on the memory controller for evaluating gross memory stability issues.
    Then I would enable it after several days of non-ECC operation, if all was well.
    I'm not sure if that made sense, and even less sure with the advent of DDR5.

  • evanhevanh Posts: 11,849

    I've never delved into the details of use. Not something I'd considered having for the longest time but might be on the cards in the not too distant future ...

  • xoroshironotxoroshironot Posts: 300
    edited 2021-06-25 16:32

    Since the 5950X has become available at only a few dollars more than MSRP, I went ahead and ordered one.
    My son has a spare 16GB of RAM (for 32GB total) he is not using, so I think I am covered for running PRNG statistical analysis and benchmarks (which I'm hoping will be at least 60% faster than my 24C/48T workstation/server).

  • evanhevanh Posts: 11,849

    Hand in the candy jar again!

  • @evanh said:
    Hand in the candy jar again!

    You might succeed in guilting me if I spring for a next-gen core monster!
    I just added the extra 16GB to the 3700X in preparation, and picked up a few nice gains in Passmark with the 3700X:
    Now CPU 23711 (mostly due to Prime Number and Physics sub-tests) and Memory 3410, both a few percent faster.
    GPU is 7% faster, but not sure if driver was upgraded since original run.

  • evanhevanh Posts: 11,849
    edited 2021-06-26 07:14

    Ah, cool, I didn't know there was a Linux version of that test. Just run it now myself and got CPU score of 19,212 - https://www.passmark.com/baselines/V10/display.php?id=500319919241
    Te-he, a little off the chart - https://www.cpubenchmark.net/cpu.php?cpu=AMD+Ryzen+7+1700X&id=2969

  • evanhevanh Posts: 11,849

    Cool, another comparison: Here's a 3700X using identical DIMMs as me. Namely 2 x G Skill Intl F4-2800C14-16GTZ - https://www.passmark.com/baselines/V10/display.php?id=123781016961

    So, just because it's a 3700X vs my 1700X, he's getting a lot more out of the DRAM. The latency difference stands out: 1700X at 48 ns and 3700X at 37 ns.

  • I got the 5950X installed and ran Passmark: https://passmark.com/baselines/V10/display.php?id=142325021046
    I'm within the top 2000 globally! I am kind of impressed, as the hardware is all somewhat mediocre (by current standards), except for the CPU.
    I also ran a full set of custom PRNG benchmarks (attached) on my xoroacc128fp/xoroacc128gp, and various xoroshiro/xoshiro.

  • evanhevanh Posts: 11,849
    edited 2021-07-02 03:16

    There's no ranking for Linux benchmarks. In fact my results aren't even included in the 1700X graph. :(

  • evanhevanh Posts: 11,849

    @xoroshironot said:
    I got the 5950X installed and ran Passmark: https://passmark.com/baselines/V10/display.php?id=142325021046

    That's DDR4-3200. I thought your son had 3600 rated DIMMs.

  • @evanh said:
    That's DDR4-3200. I thought your son had 3600 rated DIMMs.

    He pulled the 3200 and put in 32G of 3600 (as I recall).
    I'm actually am not sure why it is running at DDR4-3200, as the BIOS D.O.C.P set it, but it is actually a mix of my original 3000 + his 3200.
    I always though it would run at the lowest common denominator... maybe an ASUS bug. I'll investigate and run stability tests later.

  • evanhevanh Posts: 11,849

    Oh, is this his second hand bits you're cobbling together with a new CPU? I thought you might be upgrading his gaming machine.

  • I am just replacing my CPU and adding his old RAM to the slightly used water-cooled PC I bought in February.
    I might sell the 3700X I pulled out, but haven't decided.

    The only upgrade my son has done since replacing the RAM was to add a second SSD (this week, coincidentally).
    When the new SSD was connected and powered up, the motherboard red-lighted.
    It eventually powered up, but with only half the RAM, so I had him reseat both 16GB sticks, which worked.
    I've seen that happen with brand new Dell and HP PCs, enough to consider it an endemic issue, likely due to manufacturing residue and/or oxide.
    I always install, eject and re-install.

  • evanhevanh Posts: 11,849

    Oh, yeah, I do remember talking about that setup now.

  • xoroshironotxoroshironot Posts: 300
    edited 2021-08-06 17:02

    @evanh said:

    @xoroshironot said:
    I was guessing the vias were already present in the base chiplet design ...

    Ah, I guess that's a possibility. Would explain a lot. Also means it has been in the plan for a while. It's either that or a new layout - which does happen.

    Definitely already present: https://www.tomshardware.com/news/amd-3d-vcache-in-development-for-years

  • evanhevanh Posts: 11,849

    Better send your 5950X back for a refit then. :P

  • @evanh said:
    Better send your 5950X back for a refit then. :P

    Not the best investment I've made, so far... my youngest son has usurped the PC for the Summer, mostly for gaming.
    Once school starts in a month, I'll kick him off it. If he keeps his grades up, I may give it to him when he starts college in another year.
    That way there will (hopefully) be fewer regrets on my next system...

    Except for the possibility of fire. Did you see that some of the DDR5 will reach up to 12600 MT/s?
    With the on-module VRMs pumping out about 1.6v, perhaps start investing in fire extinguisher company stock. :neutral:

  • evanhevanh Posts: 11,849

    @xoroshironot said:
    Except for the possibility of fire. Did you see that some of the DDR5 will reach up to 12600 MT/s?

    That is high! No I hadn't read that.

    With the on-module VRMs pumping out about 1.6v, perhaps start investing in fire extinguisher company stock. :neutral:

    Certainly, that's another dimension to enthusiast grade DIMMs. And the marketing ... pictures of rockets!

  • Evan, regarding previous L2 & L3 cache discussions...
    New IBM Telum CPU will have no L4 or L3.
    L2 is higher latency, but size is large enough to offset the difference.
    https://anandtech.com/show/16924/did-ibm-just-preview-the-future-of-caches

  • evanhevanh Posts: 11,849

    I saw a headline earlier but haven't read any details till now. 32 MB per core, of actual physical SRAM, is really big no matter what level. L3 on Zen3 is 32 MB per chiplet (8 cores).

    It is what I was thinking of though - Make the space of L3 accessible to L2 use.

  • evanhevanh Posts: 11,849

    The term "chip" has become vague. Sometimes it means die, other times it means package.

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