There will be a performance difference for Grid that show 100 and 600 row of data. However, in my test the performance diffrence is small.

Attached is the test page I am using to test the scenario, I used IE8 for the test browser. You mention you have some clientside script on the Grid, does removing the clientside script make the Grid run faster?

I knew someone would ask about the scripts. But no, they don't make the Grid slow because when I remove them there is no noticeable difference. It's the Grid itself which is slow. Scrolling, editing, accepting changes, ...

Most of our clients use IE6 or IE7 and their computers are not the fastest on the market. That's why I was hoping somebody could give me some advice how to make the grid more responsive, use less resources and things like that.

Based on my discussion with the developer, he suggest to narrow the displayed data. Since paging will not be a viable option, he sugeest using filter to only display a smaller number of data.

The slowdown occurs because the browser will need to process a large number of html element.