Welcome, Scott.
Yes, your points are showing up:
http://folding.extremeoverclocking.com/user_summary.php?s=&u=651930 With those cards, you should probably follow
this guide to maximize the PPD of your 780s. Core 17 does way, way better PPD-wise than core 15, which I'm assuming your cards are running based on the PPD you're getting.
Don't increase the memory speed. FAH is not memory-intensive, so overclocking it will just result in higher temps/power draw without speeding anything up. It's possible to actually underclock the GPUs as much as possible (-500 MHz in Precision) without slowing down folding, but I assume you use these cards for gaming or something and wouldn't want to take quite that drastic a route.
As for clock speed, increasing that can make a noticeable difference, especially when you're running core 17 WUs. I have a pair of 780s, one an SC and the other a FTW. The SC at its factory OC got around 140k PPD; I believe that was around 1044 MHz boost. I was able to run it at 1215 MHz boost for several months without changing the power target, and that gets around 180k PPD. I've since had to back down a bit to 1201 MHz boost due to instability, where it gets around 175k, but that's still a 25% improvement. The FTW runs fine at 1215.
You should be aware that, at least from what I've seen, the 780s are not folding-stable at the above-mentioned OC's on core 15. I think the highest I can get on the FTW there is around 1175 MHz, and the SC can only do about 1140 or so. With the beta flag right now you'll pretty much only get core 17, but that's subject to change at any time; the beta flag is not intended to be a more-PPD setting, it just happens to be for Nvidia GPUs at the moment. You may want to run at a slower speed just so that any unexpected core 15 assignments don't cause you to start failing left and right.