Windows 10: Memory Management Crash

So I ran memtest for 32 hours and did 12 passes. No errors.

 

So I did a full reinstall of Win10 (not an upgrade from 8.1 like last time) on an SSD drive and it was working fine. Suddenly, as I was downloading a game, it started working REALLY slowly, the screen turned black and it restarted (so no BSOD that I can tell).

Here's all the information after that incident:

p.s.
For some reason the dmlog didn't include the minidump this time (said "path could not be found"). I also couldn't find it myself so I went ahead and changed the setting in windows to generate a small dump so hopefully it will generate it next time.

 

A quick event logs view shows that a service from Steam couldn't connect & that there were problems installing drivers for a USB device which was ~30 min before the restart, between the time there were no useful logs.
Code: Event[561]: Log Name: System Source: Service Control Manager Date: 2016-05-11T10:55:39.522 Event ID: 7009 Task: N/A Level: Error Opcode: N/A Keyword: Classic User: N/A User Name: N/A Computer: DESKTOP-FQ4L2N8 Description: A timeout was reached (30000 milliseconds) while waiting for the Steam Client Service service to connect. Event[562]: Log Name: System Source: Service Control Manager Date: 2016-05-11T10:55:39.522 Event ID: 7000 Task: N/A Level: Error Opcode: N/A Keyword: Classic User: N/A User Name: N/A Computer: DESKTOP-FQ4L2N8 Description: The Steam Client Service service failed to start due to the following error: The service did not respond to the start or control request in a timely fashion. Event[571]: Log Name: System Source: Microsoft-Windows-UserPnp Date: 2016-05-11T11:19:09.867 Event ID: 20003 Task: N/A Level: Information Opcode: Info Keyword: N/A User: S-1-5-18 User Name: NT AUTHORITY\SYSTEM Computer: DESKTOP-FQ4L2N8 Description: Driver Management has concluded the process to add Service usbscan for Device Instance ID USB\VID_04B8&PID_0130\5&326029A5&0&2 with the following status: 0.[/quote] Why there is no dump created?
A restart & shutdown & freeze crash are NOT the same as a BSOD crash.
Only a BSOD crash creates dumps, the others cannot do that because the others aren't crashes where data can be corrupted and Windows can catch the problem.

 

Why there is no dump created?
A restart & shutdown & freeze crash are NOT the same as a BSOD crash.
Only a BSOD crash creates dumps, the others cannot do that because the others aren't crashes where data can be corrupted and Windows can catch the problem.[/quote] I normally get BSOD crashes, but this time it was the same sluggishness I was complaining about since the very beginning, but instead of generating a BSOD, it just went all black and restarted. I changed the setting now to generate minidumps (it was a fresh install so it was by default on a different setting) and NOT to restart next time.

But I too was surprised that a minidump wasn't generated.

Any ideas why it would just go black and restart (while being extremely sluggish prior to that) and not generate a minidump?

 

Can be many things, like the PSU not giving power to the GPU causing the display to disappear causing the system to reboot as the PSU can't give enough power anymore.

I suggest that you read this post by @Arc describing many possible things causing a reboot or shutdown.
My personal opinion is that restart & shutdown crashes are a lot worse to troubleshoot than BSODs, simply because they leave usually 1 log behind that says a power issue has occured. I've (tried to) helped troubleshooting many restart/shutdown crashes and most of them did leave only that log behind which was the most informative and I consider that event log not informative at all (unless you're not aware of the power issue).