Here's a list of the special new features of Fermi:
As the foundation for NVIDIA's family of next generation GPUs namely GeForce(R), Quadro(R) and Tesla(R) "Fermi" features a host of new technologies that are "must-have" features for the computing space, including:
C++, complementing existing support for C, Fortran, Java, Python, OpenCL and DirectCompute. ECC, a critical requirement for datacenters and supercomputing centers deploying GPUs on a large scale 512 CUDA Cores(TM) featuring the new IEEE 754-2008 floating-point standard, surpassing even the most advanced CPUs 8x the peak double precision arithmetic performance over NVIDIA's last generation GPU. Double precision is critical for high-performance computing (HPC) applications such as linear algebra, numerical simulation, and quantum chemistry NVIDIA Parallel DataCache(TM) - the world's first true cache hierarchy in a GPU that speeds up algorithms such as physics solvers, raytracing, and sparse matrix multiplication where data addresses are not known beforehand NVIDIA GigaThread(TM) Engine with support for concurrent kernel execution, where different kernels of the same application context can execute on the GPU at the same time (eg: PhysX(R) fluid and rigid body solvers) Nexus - the world's first fully integrated heterogeneous computing application development environment within Microsoft Visual Studio
More details and a Fermi architecture whitepaper can be found at NVIDIA.