slow rendering on IE8

[mve]

Dear Isomorphic

I use SmartGWT 2.4 Pro.

I wonder why the same ListGrid is rendered in Chrome more than 10 times faster (<1s) than in IE8 (>10s).
The ListGrid contains about 400 entries with 8 columns. Each entry represents a group which is initially expanded (open).

How can I speed up the rendering in IE8?
Paging is not an option due to restriction in the backend.
Are there any properties on the ListGrid class which slow down the rendering specific on IE8 (e.g. AutoFitFieldWidths())?

Is the latest SmartGWT version 2.5 faster?

Any other ideas?

Thanks in advance
Marco