If you have integrated+dedicated graphics in a laptop, and the dedicated card is an ATi one - go into 'Switchable Graphics' in Catalyst Control Center, and make sure Blockland's assigned to High Performance. Mine assigned this automatically, once I finally got CCC to install properly after it mysteriously disappeared entirely from my system.
It pulls ~25fps looking at all of the Afghan DM save on High settings. ~40 on Low. Playable but not amazing. Hits vsync on Minimum, which is good enough. Before I fixed the driver issues, it wasn't swapping to the dedicated GPU and I was getting the 'packet' error - seems to be the Intel one not supporting a recent enough version of the GLSL language or a proprietary extension. Shows in the console as 1.something with an Intel revision number after it - my desktop and the laptop dedicated show 4.20.
some recent computers (like mine) uses two graphics cards, one is intel 64 mb for buisness and battry saving and the other one is nvidia 1gb for gaming... i can't enable shaders... That's a nice bad work we have here...
As for you - check in the nVIDIA control panel. If it's an Optimus setup, there should be options in the driver control panel to force dedicated/integrated rendering for different applications, from a quick googling about. It's meant to swap automatically if the integrated is under enough stress, but I get the feeling swapping devices at runtime will cause more issues than it solves in this case.
If you don't have the Optimus UI in the driver panel, try updating to the latest nVIDIA driver - apparently some machines aren't supported, but if you can update it should detect the dual cards and install the right handlers. Been hearing about nVIDIA dropping support a lot lately.