Odd Reboots when Idle

[ThreeDee]

I'm experiencing an odd issue .. my PC randomly reboots when sitting idle for a period of time.

When I'm using it whether gaming, stress testing .. video encoding .. no issues whatsoever. .. but let it sit overnight not doing anything and it will have rebooted with event ID's 18 and 19 in event viewer.

Fresh install of Windows 10 2004. 3700x stock,Noctua cooler,2 x 16GB 3200mhz@3800mhz fclk 1:1 (happens stock settings too), ASRock x570 Steel Legend, 2 x 512gb NVMe SSD's, 1 x 1TB hdd, 5700xt stock, 850wtt EVGA GQ 80+ gold, 6 RGB 120mm fans, big Rosewill case, RGB big mouse pad,RGB gaming mouse, RGB mechanical keyboard, 2 x 24" 1080p monitors.

I've updated the BIOS, PBO on or off, Memory XMP or tweaked .. still reboots when idle.

I can play Hunt:Showdown for hours, re-encode multiple video files with Vidcoder, do 25 runs of TestMem5 with custom config 1usmus_v3.cfg, AIDA64 stress test, whatever benchmarks .. all without issue/errors.

Google'n comes up with varied results .. some say damaged motherboard or PSU .. some say CPU is bad .. some say problem fixed with a cumulative Windows update.. looking for any input as i don't have components to easily swap out

 

[learners permit]

Ram speed @ 3200Mhz=f clock1600Mhz not 1900Mhz.

 

[ThreeDee]

Ram speed @ 3200Mhz=f clock1600Mhz not 1900Mhz.

?
3200mhz w/fclk 1600 .. or 3800mhz w/fckl 1900 .. still reboots when idle

 

[learners permit]

Try clear cmos and stick with 3200 1:1 first and see how it goes. I’ve seen this happen when termination resistance and memory voltages aren’t well matched by the bios. Try lower or raise memory voltage. I like ryzen master to check termination resistance to determine which way to go with memory voltage.