Well the IMC speed for a Phenom II is also known as HTT (Hyper Transport). It links the CPU to the memory directly instead of having to go through the North Bridge. Its faster and more efficient.
As said, all Phenom IIs have a 2GHz HTT link, some are 1.8GHz and a few are 2.2GHz.
Intel based chips, Core i series and up use whats called QPI or DMI. QPI is a memory link that supports 2.4GHz, 2.93GHz or 3.2GHz and memory speeds of up to 25.6GB/s. DMI is up to 20GB/s.
Here is a article from AMD:http://developer.amd.com/documentation/articles/Pages/126200550.aspx
As said, you don't need to worry about it that much. Its really fast and for gaming, it wont be as important as the GPU and resolution.