Performance comparison for MMAPv1 and WiredTiger

1. Write performance is good when using wiredtiger as a storage engine.
2. But read performance is very poor compared to MMAPv1 engine.

Hardware Configuration: Ubuntu 12.04
CPU Cores: 2
RAM: 8GB

We ran scenarios with both MMAP and wiredtiger using the same above hardware configurations. Now we finally are in a position to conclude that MMAP gives us a better performance compared to WiredTiger engine.

Help would be appreciated.

Is there any specific configuration params available to increase the read performance.