DDebbil

Well, I changed to A1 and A2, but the motherboard flashed up a message to say the RAM was in a non-optimal arrangement, and directed me to put it back into A2 and B2. According to the manual, A2 and B2 is the right arrangement.

This could be the issue - I have the RAM installed in A2 and B2 (both red lanes).

By the way, does your motherboard do what looks like an extended memory test as part of its POST procedure (lasts about 10-15 seconds)?

Neither XMP profile would POST.

Regarding overclocking first, I also tried setting 3.8GHz @ 1.35V (I know it will run 3.9GHz at that voltage), with all the memory settings mention above, and the result was no POST again.

The only thing in the RAM guide I hadn't tried already was manually setting the SOC voltage. I tried at all the settings on the side of the RAM but with 2666MHz instead of 3200MHz, and with the SOC set manually at 1.2V - but same result: no POST.

I'm trying to get a Ryzen 1700 up and running with an MSI X370 Gaming Plus motherboard, however it will not allow me to touch the RAM settings at all. On 'auto', the RAM runs 2133MHz, however even if I just manually set 2133MHz instead of using auto, the motherboard will not POST. Needless to say, no other speeds or settings can be set either. I've tried it with several kits of RAM, including some Corsair LPX that I thought was on the QVL, but when it turned up it was the right model but a different version (ARGHHH), but since even manually setting the default speed won't work, I don't think that's the issue. I have the latest BIOS from MSI on the motherboard. Does anyone have any ideas how to fix this problem?