BSOD with all cores enabled Xeon E3-1275v5

Hi,

i have a Xeon E3-1275v5 with S1200SPLR mainboard with windows server 2012 R2

all of a sudden it crashed and looped with error IRQL_NOT_LESS_OR_EQUAL

it did a BSOD trying to boot windows media as well (when trying to install to a new HDD)

after much digging i tried this

Temporarily change BIOS settings:

1. BIOS> Advanced> Processor Configuration, disable Intel® Hyper-Threading Tech, and set Core Multi-Processing to 1.

windows would boot after this but it was slow

but when i renabling it to use all cores it did the same thing

so . is this a CPU issue

i have replaced the mainboard and tried using each ram separately and still didnt work

Stav