I think it would be helpful to have a list of the hashes we achieve using different CPUs and OS. I will start by saying that I get:
- 110 hashes/sec when using 7 out of 8 cores on an i7 4770K (1150/3.5GHz/8MB) running Windows 7
- 40 hashes/sec when using 4 out of 4 cores on the Surface Pro 2 (Intel Core i5-4300U, Dual Core 1.9GHz) running Windows 8.1
Try using 3-4 cores on your i7. I'm getting 150 h/s using 3 cores (also i7-4770k). Anything past 4 and the hashrate drops.