No need to apologize fella. Just help you get a stable machine for the time being and something you can have a discussion with OCUK if and when you need to call them.
I've just installed Precision X1 myself.
So under the memory and GPU in the 'clock' boxes on the left they read '0'? If yes then the card is at stock.
Slide the memory by 100Mhz to the left so it show -100Mhz
and also for the clock for the GPU so it reads -100Mhz
Click number 1 on the right hand side and then save, bottom right.
Under 'setup' top right hand corner
'General' and tick 'start with OS' and 'start minimized'
Now try and have a game etc. Under the HWM tab after a gaming session note what the boost clocks are doing - will probably still exceed 1650Mhz.
Let us know how you get on.
My machine under certain games will be stable but there are some games like insurgency Sandstorm that are really heavy on the GPU and I got that same crash and it was annoying as it was OK in other games so was hard to pinpoint. Give it a go with the underclock and see if you can get the same crash or it becomes stable.
Thanks very much, I will give that a go.