Was the card brand new? It could have been a refurb tbh
I looked around the net earlier and some people are seeing 53 idle. Let's face it that's still a lot lower than a fast Nvidia card. It could just be because it's summer outside dude or something equally as innocent. I wouldn't worry though as XFX offers a double lifetime warranty (both you and whoever you sell it onto as long as you inform them).
TBH mate sometimes it's better to leave well alone, stop fiddling and enjoy. I know how hard that can be after a wrath of problems but trust me, don't get caught in the fiddlers trap
When my 280 died it really threw me. I had actually sold it (agreed sale) to my cousin and was just about to hit the order button on three 250GTS. That was on the day of my birthday, my 280 decided to die and screw up my birthday present. I was gutted tbh. Not only did I have to find £125 for the first 5770 as an immediate replacement but I ended up getting screwed on the 280 replacement - another 5770, losing me £60 or so.
That was what inspired me to build a second rig. I no longer trusted my PC as it just seemed to be problem after problem and my OCD for pissing with it all the time and running tests kicked in. It just made me miserable if I'm honest. It's also impossible these days to return anything by phone so a working PC is a must. That's also why I have an enormous pile of spare parts under my bed. Hard drives, GPUS, CPUs etc etc. I sell nothing now.
Get Dirt 2 on and play the crap out of it. Seriously when you begin to actually see it DX11 will just blow your fricken mind. It's not just what the reviewers said (some wavy flags) it's the lighting and everything. DX11 allows proper coloured lighting instead of just chucking white brightnes over everything. When the sun falls into the dashboard you will see what I mean. You can almost feel your face glowing from the sun.