Got it in the mail, opened it up, opened my computer, opened the instructions and--wham, turns out it needs either 2x 6-pin cables or 1x 8-pin express cable. My current PSU (500w) didn't have two 6-pin cable or an 8-pin cable. The manual also advised against turning two 4-pin cables into one 6-pin cable with the converter.
I'm no expert (if you couldn't tell) but I'm not a newbie either. I knew my old PSU was crap and now it's clear that I have to update it.
I went to several hardware shops only to find out that anything above a 400w PSU is only available online.
I live in Korea which complicates things a bit, and the most respected PSU I can find around these parts is the ZM600-HP: