Good intel processor for the GTX 570

Hello I intend to buy a custom made computer with the GeForce GTX 570 for doing scientific computing with CUDA. Since I intend to run medium/heavy duty CUDA applications on it, can you recommend a good processor in the
i5 series.

What do you think of the following CPU’s (especially the flop throughput and sturdiness ) which seem to be fitting my budget well.

Intel Core i5 650 3.2GHz (Dual Core) 4000K
Intel Core i5-2300 Sandy Bridge 2.8GHz Quad Core 6000K

I intend to use 8 GB RAM for both.

Both those CPUs are totally different sockets… The i5 2000s on the 1155 socket are vastly superior.