You can read more about it if you have Enterprise Edition, and I’ve thought it was a good start to controlling and throttling the resources inside SQL Server. I’d like to see it expanded, and I do like the CAP addition in 2012.
However I wasn’t aware you could prevent someone from enabling Resource Governor. Apparently you can, as shown in this blog: Disabling Resource Governor permanently (somewhat). Amit Bansal shows that if you set trace flag 8040, the Resource Governor cannot be enabled. This prevents changes by junior administrators, developers, etc. that might not be aware of the consequences of their actions.
Personally for me, I’m not sure I like this. To me this is a case where you don’t have trust among your staff, or good communication, or perhaps something else. None of those are good situations.
I don’t know that I’d ever use this, but you can read Amit’s post for more details.
Note that this doesn’t remove Resource Governor, and your DAC still resides in the internal pool, which always has guaranteed resources.