A couple of things to verify: do you have an air bubble in the cooling system; did you get the thermal paste put on good underneath the heat block; is your coolant circulating.
I have no idea how to verify any of those things - it's a Dell XPS730 and all I know is that it looks pretty and goes fast

I've avoided mentioning the D word before because I know I'm going to get a load of "oh well, what do you expect", but living overseas and wanting an English language everything left me with few choices!

I'll let them sort it out.

Ever the optimist....