You don't have to touch the power target with the GB cards (unless you've flashed it to a 1.212V bios then MAYBE you want to bump it). Their power target is calibrated much higher than the other 670's due to their additional 2 pin connection.
Aside from maybe in Furmark, the GB 670's never get anywhere near 100% power usage (usually they're at 75-80%, and the highest I've seen in 8 months is 91% usage), so bumping the target up does absolutely nothing on these cards.
And to answer the original question, I have to say yes it's possible
that all three cards have the same KB value out of the box, but it's statistically wildly unlikely. Even getting two that are the same is probably only about 1/10 chance. So add a third and it's more like a 1/100 chance. Have you observed the actual operating frequency on full 3d load in Afterburner or PrecX yet?If they truly are all running at the same max boost when put under a full 3d load like Heaven or 3dMark, then I'd say the most likely reason is that nVidia has adjusted the operation of the particular driver you're using to direct this behavior to happen (I'm pretty certain if they did that, it'd be because they're SO tired of having to answer constant queries from people complaining about the OPPOSITE behavior from what you're seeing ).
But then again, I'd think people would be talking about that change here on OCN, and I've not seen mention of it. What driver version are you running?
Nevermind, I thought we were talking about SLI operation, just saw your post that says you're not ... so ... yeah ... about 1/100 odds of this happening, at best. Damn near miraculous
Lastly, have a look at the first link in my sig ... all these cards have a Kepler Boost value, and that's what you'll get added onto your boost clock UNLESS there's a thermal or power limit (like I say, that will never happen on the GB card), or the load is too low to force the full KB to kick in.
There's a lot of nonsense articles out on the web that suggest that these cards will keep on boosting all the way up until 'conditions' (like temps or power usage) dictate that they can't go farther, but that is incorrect. They all have a limit/max boost that they'll inherently reach, even if they're running at 20% power and -50C. To make 'em go faster, you have to raise the boost clock (i.e. overclocking).Edited by brettjv - 2/1/13 at 10:42am