C-Ray is one of our favorite multi-threaded ray-tracing benchmarks and here the performance of the Core i7 970 and Core i5 2500K when both were at their stock speeds was in a very tight race. The i5-2500K ended up winning when being overclocked to 4.0GHz and beyond, but at stock speeds, it was a very tough game. Regardless, Sandy Bridge remains quite compelling considering the core count between the i5-2500K and i7-970 as well as the price difference.
POV-Ray is an industry-standard benchmark, but POV-Ray 3.6 is single-threaded. The Sandy Bridge processor obviously won here with ease and it was about 11% faster than the high-end Gulftown.
With Smallpt, a very lightweight multi-threaded path tracing program, it preferred a greater number of CPU cores rather than the i5-2500K's greater per-core performance but without Hyper Threading. It took the Core i5 2500K running at 4.2GHz to deliver similar results to the Core i7 970.