Hi BAP --
Your 680 is Kepler and it's going to get even better at some point. Folding isn't optimized yet for Kepler folding (in the code). They'll do it eventually and your monster will get even scarier.
7610: don't know what it is offhand but it probably doesn't use the "slow" larger Core_15. If it didn't do a core download when it got that WU and your core is still 4576Kb in size, you're still using the "good" one. You can of course predict the WU completion date by multiplying the tpf by the number of frames remaining.
You're learning stuff, BAP, 88C is in fact on the high side for a video card. It's not panic time but it's warmish.