If you are someone who does everything possible to get every bit of extra performace out of your system, and like higher 3dmark scores then yes.
If you dont like doing that and/or dont give a toss about 3dmark scores, then no.
In games, there is almost no increase. Maybe 1-2fps, or a ever-so-slightly faster load time. In windows, you would`nt really notice at all.
Ive tryed it on several systems, and both me and my friends cant see much of a difference, if any at all.
But thats just me. Others will no doubt argue against this, but from from my experiance, its a waste of money.
IMHO, its a waste, and you should save the money, or put it towards something else