6 ms·

> I can't find a single non-sketchy listing for even 3200MHz unbuffered ECC memory https://www.crucial.com/memory/server-ddr4/mta18adf2g72az-3g2e1 https://www.

> I can't find a single non-sketchy listing for even 3200MHz unbuffered ECC memory https://www.crucial.com/memory/server-ddr4/mta18adf2g72az-3g2e1 https://www.crucial.com/memory/server-ddr4/mta18adf2g72az-3g... > let alone the 3600MHz you want for current Ryzen chips Current DDR4 JEDEC-approved speeds top out at DDR4-3200. Anything beyond that is technically overclocking, even if it's overclocked from the factory and marketed to run at those speeds. Assuming that your platform supports overclocking DRAM, you can also run DDR4-3200 ECC memory at 3600 MT/s, if you feel that the performance uplift is worth the risk of stability issues.

vbezhenar 6y ago
And the good thing is that you’ll know immediately about stability issues with ECC.
- jeffbee 6y ago
  Patrol scrubbing is a RAS feature of only more expensive platforms. On most hosts you are likely to learn about the issue only at the time some program tries to access the marginal page or row.
  - theevilsharpie 6y ago
    > Patrol scrubbing is a RAS feature of only more expensive platforms. All of the ECC-capable platforms I've used (including my AMD-based desktop PCs) have supported patrol scrubbing. What have you used that doesn't?
    - jeffbee 6y ago
      My AM4 motherboard doesn't offer any options for scrubbing and its manual is vague about whether ECC errors will even be reported to the operating system. By contrast my HPE ProLiant DL360 has firmware settings for scrubbing and I know the event reporting works because I see it in the logs all the time.
      - theevilsharpie 6y ago
        The operating system will explicitly tell you at runtime if ECC support is available. If this returns an affirmative value, then ECC is working. Support for patrol scrubbing is a bit more variable. It's supported in my ASRock motherboard (B450M Pro4). It was also supported in two previous ASUS motherboards (AMD AM2 and AM3 platforms, respectively), although they called it something else that I can't remember. As well, a lack of a setting for patrol scrubbing doesn't necessarily mean that it's unavailable; it could just be enabled but not user-configurable.
        marcan_42 6y ago
        This is OS-configurable. Look for /sys/devices/system/edac/mc/mc*/sdram_scrub_rate on Linux. The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. As long as the memory is correctly initialized in ECC mode, the OS should always be able to use its EDAC driver to interact with it.
        theevilsharpie 6y ago
        > The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. This isn't entirely true. The motherboard needs to physically support ECC (i.e., traces for a 72-bit memory bus need to be present) for it to work. ECC support can also be disabled within the BIOS firmware, either explicitly via a user-adjustable toggle, or by the motherboard vendor hard-coding the setting to disabled. In any case, if the OS reports ECC as working, then ECC is fully functional.
        marcan_42 6y ago
        My point is that once RAM is initialized in ECC mode, then the OS will see it. The motherboard can't support ECC mode but then screw up EDAC. That's why I said "as long as the memory is correctly initialized in ECC mode". It's a binary thing. Either the motherboard supports ECC, or it doesn't. If it supports ECC then you can always tweak the scrubbing from the OS.
Dylan16807 6y ago
Good, glad it exists, though it looks like it's only been available for about a year. I don't care about JEDEC. I care about the XMP spec that's promised to me by the manufacturer, so I can rely on it. I'm not against overclocking myself but if I'm trying to boost it by a significant amount then I have no idea what to set the timings to and there's a good chance it just won't work, with no recourse on my end. Also that module costs way more than $65.

vbezhenar 6y ago

And the good thing is that you’ll know immediately about stability issues with ECC.

jeffbee 6y ago
Patrol scrubbing is a RAS feature of only more expensive platforms. On most hosts you are likely to learn about the issue only at the time some program tries to access the marginal page or row.
- theevilsharpie 6y ago
  > Patrol scrubbing is a RAS feature of only more expensive platforms. All of the ECC-capable platforms I've used (including my AMD-based desktop PCs) have supported patrol scrubbing. What have you used that doesn't?
  - jeffbee 6y ago
    My AM4 motherboard doesn't offer any options for scrubbing and its manual is vague about whether ECC errors will even be reported to the operating system. By contrast my HPE ProLiant DL360 has firmware settings for scrubbing and I know the event reporting works because I see it in the logs all the time.
    - theevilsharpie 6y ago
      The operating system will explicitly tell you at runtime if ECC support is available. If this returns an affirmative value, then ECC is working. Support for patrol scrubbing is a bit more variable. It's supported in my ASRock motherboard (B450M Pro4). It was also supported in two previous ASUS motherboards (AMD AM2 and AM3 platforms, respectively), although they called it something else that I can't remember. As well, a lack of a setting for patrol scrubbing doesn't necessarily mean that it's unavailable; it could just be enabled but not user-configurable.
      - marcan_42 6y ago
        This is OS-configurable. Look for /sys/devices/system/edac/mc/mc*/sdram_scrub_rate on Linux. The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. As long as the memory is correctly initialized in ECC mode, the OS should always be able to use its EDAC driver to interact with it.
        theevilsharpie 6y ago
        > The motherboard doesn't really get a say on whether the OS can correctly use ECC support on AMD as far as I know. This isn't entirely true. The motherboard needs to physically support ECC (i.e., traces for a 72-bit memory bus need to be present) for it to work. ECC support can also be disabled within the BIOS firmware, either explicitly via a user-adjustable toggle, or by the motherboard vendor hard-coding the setting to disabled. In any case, if the OS reports ECC as working, then ECC is fully functional.
        marcan_42 6y ago
        My point is that once RAM is initialized in ECC mode, then the OS will see it. The motherboard can't support ECC mode but then screw up EDAC. That's why I said "as long as the memory is correctly initialized in ECC mode". It's a binary thing. Either the motherboard supports ECC, or it doesn't. If it supports ECC then you can always tweak the scrubbing from the OS.

Dylan16807 6y ago

Good, glad it exists, though it looks like it's only been available for about a year. I don't care about JEDEC. I care about the XMP spec that's promised to me by the manufacturer, so I can rely on it. I'm not against overclocking myself but if I'm trying to boost it by a significant amount then I have no idea what to set the timings to and there's a good chance it just won't work, with no recourse on my end. Also that module costs way more than $65.