It's parameter sweeps of a delay differential equations, one simulation per thread. This requires a lot of complex array indexing and global memory access, so arithmetic density isn't near optimal. Still, it's a real world workload that benefits hugely from GPU acceleration.

Moving from a GTX 480 to a Kepler or Maxwell card, the numbers go up, but not the performance. I might have a corner case, but before investing in new hardware, I would want to benchmark first and not blindly follow the numbers.