4960X. It is clocked 100MHz higher, it is on the new Ivy Bridge-E architecture (meaning around 5% increase performance per MHz compared to I7 3970X). The 4960 uses 20W less, meaning a bit less heat and easier to cool down and allow higher OC. Unless you get a bargain a big discount on the 3970X then it is a better option. The 4960X should be around 5-7% faster while using 20W less power.