I have a similar problem on those 2 maps. Although my FPS never seem to drop below 50, it's still very annoying. I'm using 680s in SLI, 1920x1080, using the Ultra settings. I've tried everything under the sun to fix the problem, and as far as I can tell it's just a bug in the game. Using GPU-Z, my GPU usage never gets above 50% in BF4, so the game is not utilizing my cards properly. In contrast, the 3DMark app uses 100% of my cards in SLI and my scores are where they should be for my specs.
As a comparison, I have a couple of machines with single 780 cards, 1 of which has a significantly slower CPU than my SLI rig. Those 780s should perform worse than my 680s in SLI, but they are smooth as butter on every map. So it appears it's just an SLI issue with the game and/or the NVidia drivers (I'm using 331.82).
I think we just have to wait for a patch. In the meantime, I think I'll just lower the graphics quality to High and disable SLI when I play BF4. ☹️
