When comparing 6.4.1 to 6.4 on exactly the same hardware I find graphics much slower.  For example switching pages in 
Helpviewer- under 6.4.1 I can see it happening from top to bottom, under 6.4 it is instantaneous.  Browser performance 
is likewise visibly slower (hovering over drop-down menus on QNX home page will even cause mouse pointer to briefly 
disappear).  This is using exactly the same hardware and swapping hard drives containing 6.4 and 6.4.1.  This is on 
standard x86 PC.

Brought over /lib/dll/devg-radeon.so from 6.4 to 6.4.1 and slowness remained, so I don't think it is due to the driver. 
 Did anything else change?