Chart Control in C# (.NET) Uses Tons of CPU

I am using a FastLineChart in C# to display a signal from an external device in real time. The sample rate is about 700Hz. In my program I down-sample to about 100Hz to minimize unnecessary resolution for the display, but still use way too much CPU doing this.

I think the problem is that I am scrolling the data across the chart (like the CPU graph does in windows) and this is eating up resources. I do this by removing the oldest element and then adding a new one to the specific series (as shown below).

timeGraph.Series[0].Points.RemoveAt(0);
timeGraph.Series[0].Points.AddY(average);

The CPU load is about 30% which I think is a bit too high. I do not have the newest computer, but it is a Code 2 Duo with GT9600 graphics card.

Does anyone have any suggestions? Is there a better way to do this? Or a specific way to make this faster?

Thank you for any help!