http://bugs.winehq.org/show_bug.cgi?id=14391
--- Comment #10 from billstei billstei@hbci.com 2010-06-13 13:19:32 --- Regarding transparency StreamHijacker produces the following error on stdout:
fixme:x11drv:sync_window_opacity LWA_COLORKEY not supported
The question is whether this is also the source of the slow drawing/CPU spikes, or is just coincidental. Also note Bug #23093 but there is no mention of slow drawing (so far).