I dont know why they did it either, but as an overclocker I love it
It gives me a good feeling running my card over 50% faster than reference speeds.
There is a school of thought that AMD left the cards with a lot of overclocking headroom so they could upgrade the bioses as an easy counter to nvidias releases, but we will never know.
50% ?!?!?!? That's a pretty good overclock even for a 7950. in light of that i'm not going to tell what % overclock mine passed stress testing but i thought it was pretty decent, until now

Thanks for that, lol.