Constant BSOD and Cache Hirearchy Errors on self build PC

Hi,

I hope someone can clue me in on what s going on with my system. Windows 7 Home Premium 64bit.

I am having regular BSOD code 124 WHEA errors. When I look in the event viewer I have lots (100+) error id 19 WHEA errors "Cache Hierarchy Error" (usually on Core 2 but occasionally on core 3). I get a bunch of them on start-up and then 1 every 60 seconds until BSOD which happens at seemly random times and on any load. As likely to BSOD when gaming as when idle.

I have read every forum I can but nothing with this specific issue. I have ran every hardware diagnostic tool I can find. Memory seems fine (ran memtest86 for 14 hours with no errors), I replaced the PSU (CX750 with a EVGA 850W G2, I know its overkill for my system but I got it for a good price). I have stress tested the CPU with Intel Extreme tuning Utility and on max load for 4 hours I got max temp of 67 degrees. Idle temp is around 28 degrees, so I don't think its a temp issue. I have carried out these tests with and without the GPU installed. I have no overclock and the latest BIOS.

I tried a clean reinstall of windows and with nothing but the OS loaded I was still having the same issue. I tried an update to windows 10 and it would BSOD 20 seconds after loading my desktop in a continual loop. So I went back to Windows 7.

I also get the error in safe mode but no BSOD. I can remove the errors by only enabling 1 core in the BIOS. Everything else in the BIOS is at its default settings. As far as I can tell all my drivers are up to date.

I built this system in Nov 2014 and its been great, no issues at all until 2 weeks ago.

System:

i7 4790K
MSI Gaming 5 MOBO
EVGA Supernova 850 G2 PSU
Palit GTX 970
16GB (2x8GB) Corsair Vengeance DDR3 2400MHz 1.65V (running at 1333Mhz with 1.5V)
Seagate 4TB ST4000 hybrid drive
Sandisk 128GB SSD

I'll post the dump files as soon as I get a chance.

Thanks in advance for any input.

Here are the dump files from DM Log Collector.