Haswell is very sensitive when it comes to idle voltages. A lot of the existing psu's will not supply low enough voltage for idle on haswell. As a note, your psu is shakey at best - huntkey has had some pretty severe ripple issues and is not known for its quality. You should really think about getting a quality psu - if the huntkey goes, its liable to take your cpu, gpu, m/b and maybe your house with it.
Also, the increase in performance of haswell over ivy or sandy is not that great and, IMO, not worth the price.