Dell Laptop Runs Slow When Docked

My Dell 7440 work laptop ran great at work but it was running increasingly slower at home. It finally got to the point where the CPU usage was running at over 90% capacity. When I took the laptop off of the docking station and the CPU dropped to almost 10%. Putting the laptop back on the docking station, the CPU shot back up to over 90%. So I figured there was a problem with the docking station or maybe it couldn't handle the two large displays I had connected to the dock. I did some research on the Internet - a few people stated that they had a problem with the laptop running slow and that the problem was caused by the external power supply. I just happened to have a spare power supply so I swap the supply. Problem solved!