How can I make sure my GPU is running at full Speed?  

Furmark is one way.

http://www.ozone3d.net/benchmarks/fur/

(eVGA offers a version of it to check their PrecisionX overclocking software, which is based on the same code as Afterburner)

if your using msi afterburner then just look at the core and memory clock when in a 3d application and youll see what speed its running at , Seems odd you have the ability to overclock your card but not to monitor it especially as the software is set by default to monitor core , memory , temp and fanspeed after a bit of bf4 you can see my cards are ramping up and thrott;ling when at 2d , yours will / should look exacxtly the same

Try GPUz , works well and the Sensor Tab will show the graphs like MSI AB too