Titan is the first major supercomputing system to utilize a hybrid architecture, or one that utilizes both conventional 16-core AMD Opteron CPUs and NVIDIA Tesla K20 GPU Accelerators. When complete, Titan will have a theoretical peak performance of more than 20 petaflops, or more than 20,000 trillion calculations per second. More information can be found here.
I found this neat article on the NVIDIA DGX-1 http://www.nextplatform.com/2016/04/06/dgx-1-nvidias-deep-learning-system-newbies/
Something interesting I saw was that it burns 32,000 Watts, which puts things in perspective.