What works for me is to set Offscreen Drawing to "4" and turn on
either "Framebuffer Read" or "Framebuffer Read On Move" in the Special Fixes section. You might also want to turn on "Textured Window Alignment" in the Special Fixes to fix the look of the in-game text windows.
"Framebuffer Read On Move" produces an accurate swirl, but it's very slow (at least on my card).
"Framebuffer Read" produces just a "pseudo-swirl", but my system does not experience any slowdown whatsoever. Maybe it's because the framebuffer is read only once under this option, unlike in the other option in which I think the framebuffer is read on every change of frame.
Also don't forget to turn off "Frame Skipping".
That's about it with regards to the swirl part. Again, this is what works with me, and may or may not work on your system. Anyway, I hope this helps.
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Compaq nx9010
Intel Celeron 2.6 GHz
384 MB RAM
Mobile ATI RS200 chipset
Windows XP Home