I seem to have same image flickering problem if I activate GPU acceleration in Video preference settings. Image fine if preview on external monitor activated. I have tried your suggestion of 04/08/2012 but that makes no difference. Preview monitor fine if I switch off GPU acceleration, but if I then use preview on external monitor it is jerky and out of sync and sometimes impossible to return to non preview on external monitor status. Any suggestion gratefully received. Using Vegas Pro 12 with 2 NVidia cards – GTX 520 and 580. Windows 7 64 bit. Here’s some more info if that helps:
System Summary
Motherboard ASUSTeK COMPUTER INC.
Model P9X79 PRO
Bridge
North Bridge Intel Sandy Bridge-E Revision 07
South Bridge Intel X79 Revision 06
CPU
Name Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz
Cpu Socket Socket 2011 LGA
Max CPU Speed 4000MHz
Memory Summary Reported by BIOS
Memory Type DDR3
Installed Memory 32714 MBytes
Available Memory 32713 MBytes
Channels 4
Maximum Capacity 524288 MBytes