Last week, I decided it was time to build a new PC to replace the aging Dell workstation I was using. I wanted to have ECC RAM, so I went with the Asus Pro WS X570-ACE motherboard. The CPU is a Ryzen 3700X. This setup should support JEDEC RAM speeds up to 3200 MHz, but it's not easy to find unbuffered ECC that runs that fast. The only one on Newegg was this NEMIX kit, plus a few other versions from that same vendor in different sizes. So I ordered it. Upon building the PC, I found that I could use the UEFI with no problem, and even update the BIOS, but every time I tried to install Windows, the system automatically rebooted a screen or two in. To see if this was a Windows-specific problem, I created a Ubuntu Live USB and tried booting from that. Still rebooted repeatedly before getting far. Then I figured, OK, maybe it's bad RAM, so I ran memtest86 for about 2 hours. No crashes, no errors.
For a few days I beat my head against the wall trying various stuff, to no avail. Then, finally, I reduced the RAM from the auto-detected speed of 3200 MHz to 2400 MHz. And it worked! The problem is, I paid for 3200 MHz RAM. But a careful examination shows that, even though this is what the label says, it's not what I got. Here's a close-up of the Micron RAM chips on the DIMMs:
For the D9VHP code, Micron's FBGA lookup shows a corresponding part number of MT40A1G8SA-075:H. Searching for that, in turn, shows a clock speed of 1.33 GHz, which corresponds to a DDR data rate of 2666 MHz. In other words, this RAM isn't rated to run at 3200 MHz, only 2666. Note that this was sold as a server-grade ECC product, not something for overclockers.
I am now going to have to find and order some real DDR4-3200 ECC UDIMMs (I did find one other source), then return the defective-by-design NEMIX parts. I would strongly suggest that everyone else stay away from NEMIX, given what appears to be less-than-honest labeling and sale practices on their part.
For a few days I beat my head against the wall trying various stuff, to no avail. Then, finally, I reduced the RAM from the auto-detected speed of 3200 MHz to 2400 MHz. And it worked! The problem is, I paid for 3200 MHz RAM. But a careful examination shows that, even though this is what the label says, it's not what I got. Here's a close-up of the Micron RAM chips on the DIMMs:
For the D9VHP code, Micron's FBGA lookup shows a corresponding part number of MT40A1G8SA-075:H. Searching for that, in turn, shows a clock speed of 1.33 GHz, which corresponds to a DDR data rate of 2666 MHz. In other words, this RAM isn't rated to run at 3200 MHz, only 2666. Note that this was sold as a server-grade ECC product, not something for overclockers.
I am now going to have to find and order some real DDR4-3200 ECC UDIMMs (I did find one other source), then return the defective-by-design NEMIX parts. I would strongly suggest that everyone else stay away from NEMIX, given what appears to be less-than-honest labeling and sale practices on their part.