Position of graph affects performance

I have an Excel 2007 spreadsheet where I track investment accounts. I have a sub-routine that updates a chronological list of values which is used to graph the progress. For the most part it works fine.

My question:
The routine runs quite quickly – around one second. However, if I reposition graph location by moving it up on the worksheet, the routine slows down. Sometimes it takes 4-5 seconds to complete (no biggie) but I’ve seen it slowdown to over 30 seconds. If I move the graph back to the original position it returns to a one second process. If I move the chart down, left, or right (just not up) the speed is not affected. Any suggestions would be appreciated?

Thanks,
Steve

I believe I found my answer. I added the line
"application.screenupdating = false"
to the beginning of the sub-routine.