Flexicious Ultimate follows in the footsteps of the SDK DataGrid to implement performance optimizations. We implement Renderer Recycling, where Similar to the SDK Datagrid, we only draw the visible area. This means, we create a set of renderers, and basically recycle them as you scroll.

Since we draw just the visible area, the memory/performance will depend more on the height and width of the grid and the number of columns you pack into the visible area. A couple of pointers to improve performance:

1) If you have a LOT of columns, set horizontalScrollPolicy to auto or on, which will use horizontal renderer recycling, improving performance.

2) If you have custom item renderers, be careful with them, if you nest too many heavy weight containers, you will run into performance issues.

3) If you have a very large amount of data (say hundreds of thousands of records), you should consider server side paging. We have a lot of information about this on our blog as well as sample code.

A lot of the advice that you have come across in terms of performance with the SDK datagrids will be applicable with Flexicious Ultimate. Alex Harui, one of the original designers behind the Halo DataGrids has some excellent advice, much of which will be applicable to Flexicious Ultimate as well:

http://blogs.adobe.com/aharui/2007/03/thinking_about_item_renderers_1.html
http://blogs.adobe.com/aharui/2007/04/more_thinking_about_item_rende.html