I’ve been looking for unbuffered ECC memory for my next virtualization/ZFS build.
There’s plenty of registered ECC DDR4, but unbuffered ECC DDR4 seems to be very hard to find.
Registered memory won’t work with Ryzen, Xeon E3-series, or Pentium/Celeron/Core CPUs. You can always go Epyc or Xeon E5-series, but both the CPUs and the motherboards are a lot more expensive unless you go for older hardware, which tends to be more power hungry and has worse single-core performance.
If you want a machine that has ECC, isn’t crazy expensive, and is also good for single-core performance (e.g. games), you really want a non-APU Ryzen 3000-series CPU and unbuffered ECC DIMMs.
Unfortunately, almost all ECC unbuffered DIMMs are 2666MHz or slower. That’s not great for performance on Ryzen 3000, where faster memory helps quite a bit.
You can overclock ECC memory. In theory the ECC should at least let you detect bit errors caused by timings that are too tight. However on a machine where reliability is critical I personally don’t want to poke the overclocking bear.
Micron has some 3200MHz modules (MTA18ADF2G72AZ-3G2E1) but they are crazy expensive - over $200 in most places for a 16GB DIMM.
Recently I discovered that Kingston now has a 16GB 3200MHz ECC module:
KSM32ED8/16ME
Provantage has those modules in stock right now for $95.
I was able to order two, and they shipped directly from Kingston in California.