It doesn't hang the system (even though it works very slowly) in the folowing combination: Radeon HD 3650 card using KDE SC 4.6.1, kernel 2.6.38 and flash (32 bit) inside Opera 11.10.2048 (64 bit). It might be because my 32 bit mesa is version 7.10, I'm only using mesa from git for 64 bit applications.