No. The 870 is an 1156 LGA, so needs new memory, motherboard and CPU. The new hex core is even worse value than the extreme, as at least that was unlocked.
The 930 is still probably the best value 1366 chip, but with the price cuts on the i5, that would be the CPU of choice on the P55 boards.
i7 3930K 4.5GHz -EK Supreme HF- Rampage IV Extreme EK Blocks - 32GB 1600MHz RAM - 680GTX SLI Koolance Blocks - Creative Titanium Pro - TJ07B-W - TCubed BigNG - 240GB SSD - 3TB HD - Dual Loop