Neither Chrome or Safaris playing properly. I guess it is a problem related to Flash 11.3. For Onyx, check all the boxes in Maintenance tab. If you want to optimize further, disable the dashboard and remove any unecessary localization files.
I'm doing some research about the hyperthreading thing and Flash on GMA500 (Dell Mini 10V forums + japanese websites). I would also love to have Video Out working on the Vaio P since the screen is very small.
BTW I have made a Clonezilla backup of my Hackintosh drive so it takes just a few minutes to restore my drive so I can test some things without fearing KP