Yup. I've a similar system as well. Except 2 650m cards running in SLI and an i7 3630QM (2.4-3.4 GHz). Somethings up and Larian has yet to give a clear and concice response. Best we can do is just keep checking daily and updating threads like these. I don't know a single person with similar specs to ours that isn't having some kind of problem with performance and frame rate.
Hopefully Larian is looking at these threads and can produce a fix soon.