alt Hacker NewsYes, ECC DIMMs are available only for the memory speeds guaranteed to work by the manufacturers of CPUs, like Intel and AMD, e.g. for up to DDR5-5600 in UDIMMs or DDR5-6400 in RDIMMs.
The "gaming" DIMMs are available in much greater speeds, which are "overclocked" speeds, i.e. there exists absolutely no guarantee from Intel or AMD that they work at the advertised speed, even if they frequently do work.
However, with such overclocked DIMMs, you do not know how well they work. They might work most of the time, but e.g. in a hotter room they might have an error or two per day without you noticing, especially if the computer is used mainly for games.
For someone doing anything professional on a computer, overclocked DIMMs are not an acceptable choice.
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AMD, Intel, and motherboard manufacturers do qualify the CPUs and motherboards for "overclocked" (above JEDEC) memory speeds. The systems are designed to work at the overclocked transmission speeds. They need to be paired with memory modules that are capable of functioning at those speeds. With ECC presently being a datacenter thing, companies only make it according to JEDEC specs. If ECC were standard for everyone, then the pre-qualified overclocked "gaming" memory modules would be available in ECC configuration as well.
Without ECC, nobody knows if their memory is working or not. Regardless whether it is running a standard JEDEC speed or an overclocked one.
So as I was overclocking my AMD Ryzen 7 2700 I discovered that the Infinity Fabric has ECC because if I tried to run my fancy DDR-3466 ram at full speed I started getting logged errors from it. Those failed transactions slow down the system because the data needs to be corrected or even re-sent. The RAM runs fine overclocked at DDR4-4200 in a newer system, but my old Ryzen 7 2700 couldn't handle anything past DDR4-3266 without the errors creeping in.
Without the reported ECC on Infinity Fabric I would have had no idea that the errors were happening and affecting performance.
> ECC DIMMs are available only for the memory speeds guaranteed to work by the manufacturers of CPUs, like Intel and AMD, e.g. for up to DDR5-5600 in UDIMMs or DDR5-6400 in RDIMMs.
This is not true[1]. These DIMMs are not guaranteed to work with all Threadripper CPUs, but they are guaranteed themselves to be stable at their advertised frequencies, which are higher than JEDEC. (And from my experience, 9000-series threadripper is perfectly happy to drive 8-channel 1Rx8 at 7200MT/s.)
AMD (and possibly Intel, I don’t have any experience with their recent offerings) also lets you overclock memory completely on WRX90. So if you buy JEDEC sticks, you’re welcome to try to push them as hard as you can.
[1] https://v-color.net/products/ddr5-ocrdimm-amd-wrx90-workstat...