Today Nvidia introduced the first card in its new 7 series of graphics cards, the GeForce GTX 780. Based on the name you probably expect an entirely new architecture, but the GTX 780 is based on the same GK110 GPU that's the foundation of the GeForce Titan. The new card has slightly fewer CUDA Cores (Nvidia's term for its unified shaders), somewhat less video memory and lower clock speeds.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips