Setting background colors - impact on performance

I have done a lot of testing of performance of large datasets. I have found that the csv file is much quicker in scrolling. The other thing that seems to impact refresh performance is a high volume of getCellTemplate().setStyle("background-color",color);

I need to set the color on and off dynamically so I'm not sure that css is the answer. Is there any way to code it to be quicker? Perhaps turn unneeded events off. What is happening when the setstyle is called?

I have found that with even 1500 records, with about 1000 getCellTemplate calls, the scrolling changes from 1-2 seconds to 4-5 seconds.