I appreciate that I am bumping an old thread, but I would like to relate my experience which is directly relevant to the OP's original comments.
I picked up an HTC One a month ago and then on Saturday set up a brand new router. Being a tinkerer, I was fiddling with this and that on the router trying to optimize everything. I also played with the phone and amongst various settings I decided to turn on "best wifi performance". The One has the warning about "may consume more power", but I did not think much about it as I knew I had very good battery life and believed that a bit more power would probably not change matters that much.
Come yesterday evening and my battery life was horrendous and I started scratching my head as to why it had gone to hell in a hand basket. Finally, I recalled that I had adjusted "best wifi performance" and did a search on this. The OP's post came up at the top or near the top (HTC One in a google search also includes HTC One X
I turned it off, recharged my phone and followed battery life keenly. It is far better today. Without a hint of an exaggeration, having "best wifi performance" on cut my battery life by 1/2 to 2/3 (just like the OP's experience).