5 ms·

I thought the same as you, but the situation's less dire thankfully. Wrote a post about it a while back that was top of HN: https://sunshowers.io/posts/am5-ryze

I thought the same as you, but the situation's less dire thankfully. Wrote a post about it a while back that was top of HN: https://sunshowers.io/posts/am5-ryzen-7000-ecc-ram/ https://sunshowers.io/posts/am5-ryzen-7000-ecc-ram/

justinclift 3y ago
Possibly interestingly, the motherboard (ASRock X670E Taichi) you mention there now has ECC listed on the ASRock page: https://www.asrock.com/mb/AMD/X670E%20Taichi/index.asp#Specification https://www.asrock.com/mb/AMD/X670E%20Taichi/index.asp#Speci... Supports DDR5 ECC/non-ECC, un-buffered memory up to 7800+(OC)
- sunshowers 3y ago
  Oh awesome. That's really fantastic. The Riptide motherboard I use also has ECC listed now. https://pg.asrock.com/mb/AMD/B650E%20PG%20Riptide%20WiFi https://pg.asrock.com/mb/AMD/B650E%20PG%20Riptide%20WiFi
- treprinum 3y ago
  "Supports" might mean you can run unbuffered ECC UDIMMs but without ECC? Even Intel can run ECC UDIMMs in non-ECC mode. Also some manufacturers don't distinguish between "on-die ECC" (DDR5) and real ECC.
  - sunshowers 3y ago
    No, the memory controller believes ECC is activated. See my post :)
Dylan16807 3y ago
Less dire for sure, but having to pay double the cost for ECC modules is still pretty dire.
- adrian_b 3y ago
  That is not true. The last time I have looked ECC DDR5 UDIMM modules had a price higher by at most 50%. Nevertheless that is still excessively high. While in the beginning for DDR5 there were only 80-bit modules, which could claim a +25% higher price, now there are 72-bit modules, like in the previous generations, which can justify at most a +12.5% price increase.
  - Dylan16807 3y ago
    I looked right when I posted that and found 2x32GB non-ECC 5600MHz for $165, exactly half the $330 price of the sticks listed in the post. I spent several minutes looking for cheaper ECC at the same specs and couldn't find any. Trying again, I can find some Kingston sticks that are $120 each, so that's about 50% higher. Amazon's search is really bad, by the way. But that's not the "at most" price. And a month ago they were $140 each. Also the spec sheet says they are 72 bit modules made out of 20 2GB x8 chips? That is baffling. Is 10% of the memory going unused? https://www.kingston.com/datasheets/KSM56E46BD8KM-32HA.pdf https://www.kingston.com/datasheets/KSM56E46BD8KM-32HA.pdf Edit: Micron data sheets suggest that UDIMMs have 2x13 command/address pins and RDIMMs have 2x6, so that's one piece of the puzzle. Apparently UDIMMs can do x64 and x72, and RDIMMs can do x72 and x80.
    - adrian_b 3y ago
      When DDR5 was first introduced, there were only x8 chips. Because the DDR5 channels must have a width of 32, 36 or 40 bits, with x8 chips one had to use 40-bit channels, even if only 36-bit channels are needed, so indeed 10% of the memory capacity remained unused. Meanwhile, about a year ago, at least Micron has also introduced x4 chips. There are such ECC UDIMMs, using both x8 and x4 chips, which waste no memory. On the market there are both modules made only with x8 chips, which do not use a part of the memory, and modules with a combination of x8 and x4 chips, without unused memory.

justinclift 3y ago

Possibly interestingly, the motherboard (ASRock X670E Taichi) you mention there now has ECC listed on the ASRock page: https://www.asrock.com/mb/AMD/X670E%20Taichi/index.asp#Specification https://www.asrock.com/mb/AMD/X670E%20Taichi/index.asp#Speci... Supports DDR5 ECC/non-ECC, un-buffered memory up to 7800+(OC)

sunshowers 3y ago
Oh awesome. That's really fantastic. The Riptide motherboard I use also has ECC listed now. https://pg.asrock.com/mb/AMD/B650E%20PG%20Riptide%20WiFi https://pg.asrock.com/mb/AMD/B650E%20PG%20Riptide%20WiFi
treprinum 3y ago
"Supports" might mean you can run unbuffered ECC UDIMMs but without ECC? Even Intel can run ECC UDIMMs in non-ECC mode. Also some manufacturers don't distinguish between "on-die ECC" (DDR5) and real ECC.
- sunshowers 3y ago
  No, the memory controller believes ECC is activated. See my post :)

Dylan16807 3y ago

Less dire for sure, but having to pay double the cost for ECC modules is still pretty dire.

adrian_b 3y ago
That is not true. The last time I have looked ECC DDR5 UDIMM modules had a price higher by at most 50%. Nevertheless that is still excessively high. While in the beginning for DDR5 there were only 80-bit modules, which could claim a +25% higher price, now there are 72-bit modules, like in the previous generations, which can justify at most a +12.5% price increase.
- Dylan16807 3y ago
  I looked right when I posted that and found 2x32GB non-ECC 5600MHz for $165, exactly half the $330 price of the sticks listed in the post. I spent several minutes looking for cheaper ECC at the same specs and couldn't find any. Trying again, I can find some Kingston sticks that are $120 each, so that's about 50% higher. Amazon's search is really bad, by the way. But that's not the "at most" price. And a month ago they were $140 each. Also the spec sheet says they are 72 bit modules made out of 20 2GB x8 chips? That is baffling. Is 10% of the memory going unused? https://www.kingston.com/datasheets/KSM56E46BD8KM-32HA.pdf https://www.kingston.com/datasheets/KSM56E46BD8KM-32HA.pdf Edit: Micron data sheets suggest that UDIMMs have 2x13 command/address pins and RDIMMs have 2x6, so that's one piece of the puzzle. Apparently UDIMMs can do x64 and x72, and RDIMMs can do x72 and x80.
  - adrian_b 3y ago
    When DDR5 was first introduced, there were only x8 chips. Because the DDR5 channels must have a width of 32, 36 or 40 bits, with x8 chips one had to use 40-bit channels, even if only 36-bit channels are needed, so indeed 10% of the memory capacity remained unused. Meanwhile, about a year ago, at least Micron has also introduced x4 chips. There are such ECC UDIMMs, using both x8 and x4 chips, which waste no memory. On the market there are both modules made only with x8 chips, which do not use a part of the memory, and modules with a combination of x8 and x4 chips, without unused memory.