Unlikely to be PSU related at this point - you're not even booting up at 3200mhz, so not even pushing the GPU, which is the most power hungry part of your build (~175w).
Much more likely you're hitting the limit of what the infinity fabric can handle on zen+.
The maximum (non-oc) official supported ram speed for a ryzen 2700 is 2933mhz.
It's double data rate (ddr) ram, so really the max ram speed is 1466mhz.
I believe the infinity fabric is tied 1:1 to this speed on zen+ (on zen2 the fabric can be set to half the ram speed).
I'd suggest running AMD's official Ryzen Master software.
Boot up using 3000mhz as it's stable there, then use the software to confirm that when you switch to 3200mhz, it will presumably freeze.
Reboot (which should be fine, as you're still set to 3000mhz in the bios), and run Ryzen Master again, this time check out the options available for your system... You might be able to achieve 3200mhz by upping the voltage or looking at fabric settings. Be careful, adjusting voltages can be dangerous if you go too far.
This is now officially an overclocking request (as 3200 is beyond the 2933 officially supported), as we've ruled out ram problems with memtest86, and there's no other evidence of any component issues. You might need to try an overclocking forum.
Your other options are to just run at 2933 (or 3000 if you like), or try to adjust the timings (say, 18-20-20-40).
The timings for your ram are officially 16-18-18-36 at 3200mhz at 1.35volts.
This won't help though if it is the infinity fabric that's the issue.
Also of note, in your bios screenshot, it's showing 3000mhz at 1.2volts. For anything above the SPD timings, you might as well set it to 1.35volts, as this is what the XMP profile does.