Live data capture and charting speed

Hi All,

I have a project whereby I am capturing live data from a data acquisition unit.
The data consists of voltage readings from two channels plus a timestamp, captured at the rate of 20 (sets of) readings per second populating a worksheet.
I have the capture of data limited to 2400 rows of data per test instance, a total of 2 minutes per test.

I would like to chart this live data so that we can watch the test progress in real time, comparing the x y relationship on a scatter chart.

I'm currently using a dynamic named range to capture only the data available at each point in (excel update) time rather than simply set the range for my chart series to pick up the full 2400 rows of data by two columns (ignoring the timestamp data).
Sometimes the test is terminated before the 2 minutes is reached.

Is this the most efficient (and hence speedy) way of getting data to the charting process quickly ?
Is there anything else I can do to pull the data from the worksheet quicker so as to have less pausing / lag between real time capture and viewing ?

I'm satisfied that the data is reaching the worksheet quickly enough (USB2 input of data stream and the worksheet updates quickly) so I figure the delay / lag is internal to Excel, trying to get the data to the chart...

Any thoughts as to how to improve this situation ?

Many thanks, Neil.