Unfortunately, the only thing that I can suggest in this case, besides using the latest version of the controls, in case you are not, is to reduce the number of items in the sparkline controls. For example, you can use some custom logic to filter the data.
But I have no idea for about custom data filtering.
Can you post a data filter example?
answered on 20 Jul 2012, 11:24 AM
What I meant by "custom logic to filter the data" was that, depending on your scenario, specific data and specification, you can reduce the data before you pass it to the sparkline. In case the sparkline controls have less points to show, the performance will be better.