Since a few weeks I have the same problem.
For the Not as dumb as I look ones:
I have an
ASUS GTX 550 Ti ... graphic card
ASUS P8Z77-v ... motherboard
Intel Core i7-3770 processor
a few SSD cards
and I run on optical wire
...
I dont think its the PC, but probably this is still not enough information.
with love,
Cin