PC Crashes while playing games and/or benchmark programs

System:
I7-6700k
MSI GTX 970 Gaming 4G (Latest Nvidia Driver)
Gigabyte Z170-HD3P (newest BIOS Version)
8GB(2x4) Corsair Vengeance DDR4-2666
700 Watt Cooler Master B700 ver.2 Non-Modular 80+ (+3,3V:22A ; +5V:22A)
256GB Samsung 850 EVO and 1TB Seagate
Windows 10 Creators Update

Issue:
I have build my PC about 1,5 years ago, everything was fine until 2 months ago. My PC started to crash while playing particular games like Playerunknowns Battlegrounds, but only rarely. Now, it crashes in almost every game beside Rainbow Six Siege (i can play that game for hours, never had a single crash). It also crashes when i run benchmark programs like Heaven or Furmark.

What i did so far:
I have installed different nvidia drivers, freshly installed windows 10, also installed windows 8.1 on a different hard drive. My system is not overclocked. I used to have my GPU overclocked for like 1 day, but then downclocked it back to normal. I set my bios to default settings and also updated it to the newest version when i freshly installed windows 10. I installed all available chipset and motherboard driver.
I tested my ram with mem86 and also my CPU with Prime95 (also rendered some videos) and no crash.
Moreover, i put my GTX 970 in my fathers PC, run different games and benchmark programs, it didnt crash once.
I also put an old GTX 570 in my pc and run different games/benchmark programs. I tested for almost an hour and it seemed not to crash, but then i started "Islands of Nyne:Battle Royale", a game where i had problems before and it crashed after 3 minutes of playing.
My temperatures are always very good, CPU does not go over 50 degree and GPU not over 70.

The windows log files are not very helpful either, it just gives me a 41 Error ->

(+ System

- Provider

[ Name] Microsoft-Windows-Kernel-Power
[ Guid] {331C3B3A-2005-44C2-AC5E-77220C37D6B4}

EventID 41

Version 5

Level 1

Task 63

Opcode 0

Keywords 0x8000400000000002

- TimeCreated

[ SystemTime] 2017-06-12T17:44:16.717953100Z

EventRecordID 6288

Correlation

- Execution

[ ProcessID] 4
[ ThreadID] 8

Channel System

Computer DESKTOP-13JOQTP

- Security

[ UserID] S-1-5-18


- EventData

BugcheckCode 0
BugcheckParameter1 0x0
BugcheckParameter2 0x0
BugcheckParameter3 0x0
BugcheckParameter4 0x0
SleepInProgress 0
PowerButtonTimestamp 0
BootAppStatus 0
Checkpoint 0
ConnectedStandbyInProgress false
SystemSleepTransitionsToOn 0
CsEntryScenarioInstanceId 0
BugcheckInfoFromEFI true
)




Any suggestions what i could also test? Could it be my PSU? I have done a lot of testing already and my next step would be to test my build with a different PSU or could it be a driver issue or something similar?


I appreciate any help, i'm very desperate at the moment.


Thank you for reading.