PhilB

The system has crashed two more times since my original post. I really need some good advice here.

I recently bought AIDA64 Extreme, version 6.25.400, dated 4/6/2020, latest available. I am hoping that AIDA64 can help pinpoint the source of instability that has caused my new system to shut down twice now, weeks apart, without any warning. In between shutdowns, it has worked perfectly normally. I have no understanding of AIDA64, so I need step by step instructions here to record power supply voltages and power output, (or other aspects of the hardware) so I can spot any issues that might lead to a system shutdown. The issue is that twice now my new system has shut down suddenly, (Windows 10 Pro, no BSOD), and I'm wondering if the power supply is at fault here, or there is some other hardware issue. The power supply is a Corsair AX850, purchased around 2014, and has been rock solid, trouble free with the prior motherboard/CPU/RAM. If the power supply is at fault, then I will replace it, but I don't want to go to the trouble and expense of a new power supply without some reason to do so. Or if the motherboard itself is the problem, I don't want to go through the hassle of doing an RMA without a reason. With the Covid crisis, it's anyone's guess how long before I would get a repaired/replaced motherboard. Aside from the motherboard/CPU/RAM and graphics card, my system contains 1 SSD and 3 7200 RPM HDDs, in other words well under 50 watts max power draw. At 850 watts output, I know my PSU is overspecified for my system, but that gives me peace of mind. My newly rebuilt my system consists of an ASUS Strix-E X570 motherboard with AMD 3900X CPU and 2 x 16 GB Crucial 3600-speed RAM. After building this system I flashed the BIOS to latest available for this board. So far, I am running at default-BIOS stock settings. I have changed nothing in the BIOS except the date, so I can be sure that the system is stable. I have not yet updated my video card, which is an old nVidia GTX 660, and which has been trouble-free since purchase. For a week, the system ran fine, and I liked the improved performance. One week after building this system, it shut down suddenly, and I could not restart it even by pressing the power button. The fans would spin for 1-2 seconds and then stop. I tore apart the system and rebuilt it piece by piece, doing reboots along the way. Before re-installing the motherboard, I used a power supply tester to verify that all voltages were within spec and that the Power Good signal was within spec. I also removed the CMOS battery and left it out overnight, so that I had to "re-initialize" BIOS values when I first powered up the system after rebuilding it. I rebuilt the system and it was absolutely stable for three weeks, no Windows crashes, nothing, until last night when it suddenly shut down again. This time, however, I was able to restart the system and run Windows normally. Right now the system is running normally. But I am concerned that there is instability in this system that I need to eliminate. So I suspect that it might be a power supply issue, but I have no firm evidence of that. That's why I want to use AIDA64 to check power supply performance. I'm open to any and all suggestions here. In general I am an experienced system builder.