FUD Zilla claims NVIDIA's GeForce GTX 590 cores will be clocked around 600MHz, a far cry from the 772MHz offered by the GeForce GTX 580. Average TDP is said to be around 375W and according to FUD the sample they saw at CeBIT (behind closed doors) was pretty quiet. Official launch is slated for March 22nd.
Bear in mind that specs are coming from various sources and nothing has still been confirmed by Nvidia, but it looks like GTX 590 will end up clocked at around 600MHz for the GPU. Those 1024 CUDA cores, or simply shaders, will end up at around 1200MHz, while the memory should be set at around 3400MHz and paried up with a 2x384-bit memory interface. The reference GTX 580 was working at 772MHz for the GPU and 4008MHz for memory.
Not straying from its tradition, Nvidia is still talking about "average TDP" which will be set at around 375W for the GTX 590. It needs two 8-pin PCI-Express power connectors, and in case you are wondering, the average TDP for the GTX 580 was 244W.