Your measurement equipment can't measure each value exactly. That is way some measurement are more expensive than others. You pay for the accuracy.
So if you measure 17345 m Watt, but the accuracy is 1000 m Watt, you can't tell anything from the just released test, as you conclude that the open source drivers are better because of the difference you are talking about is less than the accuracy.
With other words, you are only seeing noise.
That is why each measurement point needs to have an error bar, so you can tell how likely it is that the differences you see is in fact differences and not noise that comes from the measurement it self.