All of Seam when used with JSF is executed inside Servlet filters. So you have a performance problem somewhere in your app...
Try harder to isolate the problem.
Have you modified the ajax4jsf filter settings in your web.xml?
I noticed a fairly large performance boost buy configuring it to use the NEKO filter (when rendering a lot of output)!
Have look here in the RichFaces docs
This is just a guess based on the the ajax4jsf filter show in the profiler output.