You have two 7970's? And enough power supply for them (4 PCI-e connectors and 800 watts or better)?
In that case, try what amaranthy said first: go into CCC and disable Crossfire; see if that clears it up. One 7970 should be adequate for this game, with anything but Ubersampling, but two in Crossfire will expose any problems this game has with your Crossfire setup.
Also, get the latest version (2.3.0 and up) of MSI Afterburner. It has a peak frame time chart. You can use this to see whether you're actually getting skips or stutter, and exactly how bad it is.