Source is an Xbox 360 via HDMI. Recording with Media Express. All drivers/software is up to date.
Here are my Media Express settings:


Here is the results of my disk speed test:


Specs on my computer:
Intel Core i7 920, 3.8 GHz
12 GB DDR3 1600 RAM
NVidia GTX 295
4x Seagate 2 TB hard drives in RAID 0