I've gotten a lot of "junk" about cpu bottleneck and what not as well... But my 285's wont go above 75% in BF3.
I kinda new to sli, I just picked up and extra 285 to get me through till next year's nvidia cards... I don't really see a reason performance wise to upgrade to a 5xx series.
Having that said, I've come across a couple of things myself in my search for answers on the gpu usage...
If using multi-monitors... Hit "windows+P" and select "computer only" before launching a game... Leaving a unused monitor on displaying the desktop will eat gpu cycles like mad. (I couldn't get over 40% usage with my second monitor in use).
Another thing I just played with today, Firefox hardware acceleration. If using Firefox at least (might apply to other browser as well... dont know). I disabled hardware acceleration in Firefox and freed over 180mb of video ram and gained another 5-7% gpu usage in game. (Since we have to keep a browser open for freakin' BattleLog)
Other than that... there are lot of people with the Gpu usage issue. It is seemingly random however. People with 560ti, 460, 260 216's, 570's... and any run of Cpu's... I7's, I5's, core2quads, any amd ... and all at any range of clock...
Other than that... I would still OC that Proc. There really isn't any reason not to in all reality... there is free performance in there as it is.