Custom build random BSOD - Can't get to boot

[camelx]

Help please! I'm quite desperate after spending 3 days of troubleshooting, with a high probability of a failing component.

So it all started with an awesomely fun build I set up last December, working fine ever since, until this week I got a BSOD while gaming: APC INDEX MISMATCH. So the PC restarted, and I started troubleshooting in Chrome, while all Chrome extensions began shutting down one after the other, until it gave me the same BSOD message again. After a while, it couldn't even boot, giving me a random BSOD error every time after POST. So I reinstalled Windows 10, then it worked for a couple of minutes, then the same errors all over again, till I couldn't even boot again. So here was my config:

MSI B150 gaming pro
Intel i5 6600k
Corsair Vengeance LPX DDR4 2133 MHZ 2x8 GB
Samsung 850 evo 256 gb
Geforce 1070 gtx
Be Quiet! Power Zone 650W

I ran memtest, did CMOS reset, BIOS update, no luck. Then I borrowed my friend's HDD, I couldn't even instal Windows without a BSOD. Since I thought I ruled out RAM and the boot drive, I went to buy a new motherboard:

Gigabyte Z270-Gaming K3

I set up my updated build and oh relief for 10 hours... but then I got 2 crashes from a Steam game, then waited a bit, till all the running programs began to get corrupted pretty quickly, then BSOD until I can't boot, as for where I am now. I got the following BSOD messages in 1 hour's time:

APC INDEX MISMATCH
BAD POOL HEADER
KMODE EXCEPTION NOT HANDLED
IRQL NOT LESS THAN EQUAL
BAD SYSTEM CONFIG INFO
SYSTEM SERVICE EXCEPTION
ATTEMPTED EXCECUTE OF NOEXCECUTE MEMORY
UNEXPECTED KERNEL MODE TRAP

...and here I am, running memtest again, mentally really tired, but still googling for these BSOD codes one by one, thinking that even if memtest will pass, it's the RAM again, since I had a similar experience last year (memtest passed, but replacing RAM solved it)... but after buying a new motherboard, it would be painful to rush for a new DDR4 stick too. Any other ideas what can be wrong?

 

[Dark Lord of Tech]

Driver or memory issue is usually the culprit.

 

[camelx]

Driver or memory issue is usually the culprit.

Thank you for your reply! I was about to exclude any chance of driver issues, as I barely instal anything before I get the first BSODs, but now that I think about it, the brand new nvidia display driver is always up in the first place. I'll try to reach safe mode to initiate Display Driver Uninstaller and then find myself a legacy driver.

#UPDATE: after several attempts, I finally managed to remove my GPU driver, reinstal one from September, and have 1 hour of browsing the net and gaming a bit, before the crashes happened again more and more frequently, then the BSOD restart loop. I have no more ideas, I'll try to get a DDR4 RAM...

#UPDATE2: seems I just had to be persistent in doing memtests. After a whole day of testing I found one of the RAM sticks to be defective. Even to a small extent, but the mess it caused... I'm going to RMA it.