Just to be sure,
did you check your cpu core temperatures. I mean the 4 cores not the package temp.
I may be totaly wrong, but it is a verry fast check.
Download Realtemp and Prime95, extract both in the same folder.
run realtemp and run prime95 through realtemp.
It wil tell you in a hurry if your builder didn't accidentaly knock the cpu cooler and therefore throttle your cpu.(Or like in my case, tilting the case and letting a airbubble in the radiator travel to the waterblock.)
As long as the temps are below 90, then you can rule that out.(this is btw NOT an ok temp for everyday use, but after that the cpu will just slow down to a crawl)
I hope for you that it is something stupid and simpel as this.
Good luck
PS Just my 2 cents, seeing your system specs i would go for a bigger watercooler. The thin 120 rad in the h60 is not realy up to the task of keeping a 4770oced cool.