Just remember that Windows isn't the only thing that restricts your power.  There are BIOS settings to consider, and, if you're running virtual machines, there are possible throttles there too.

Something else to consider is that, just because you *can* change the setting in Windows, doesn't mean it'll stay there - if your infrastructure team has been doing stuff, then chances are there's a group policy they might need to adjust to allow SQL Servers to not be restricted like this.