I like this project... the gateway drug to mining

I sincerely hope people new to mining try it and get a positive experience. It is definitely easy to get started.
I have one computer with a Core i5 mining with 2 cores at 25 H/s and another computer with a 18 cores at 250 H/s. This is the result after mining for many hours:
| Core i5 | Xeon 20 Core |
Specs | 4 cores / 4 threads | 20 cores / 40 threads |
Mining with | 2 cores | 18 cores |
Speed | 25 H/s | 250 H/s |
Accepted hashes | 170 | 186 |
As you can see the number don't add up. The 18 core system has 10 times the hashes, but far from 10 times the accepted hashes. Why is that?