Maybe your massive GPU overclock, for the most part, cancels out the CPU driver overhead?
Eh, usually the more GPU power you give, the more CPU power you require to take full use of it. In the Valley benchmark I gain 5-10FPS for every 100Mhz I add over 4.6Ghz on my CPU.
70% gains claimed in Rome 2 and I got less than 1% of a gain...
I never expected these drivers to deliver what was claimed. It's just not realistic to expect those sorts of gains out of just a driver update. Even Mantle, which is an entirely distinct and custom API baked in on a game by game basis, only gives about 10% more performance on high end setups. There was no way a simple driver update was going to be able to do anything like that in games that have already received driver optimizations.
Maybe someone can try something like BF4 on all low settings @ 1080P on a powerful GPU setup and see if there are the kinds of 50%+ gains Mantle gives in those CPU limited situations.
The driver must do something for all the PR about it. Maybe it just needs to be tested in whatever specific scenarios it actually makes a difference under.