OK, so I ugraded flash player, as I was told to do by the auto updater. Big mistake.
Since then, all HD videos on YouTube (720 and 1080 pt) or Vimeo don't play right anymore. It can be a jerky 2 or 5 fps experience, but usually, it's a few seconds of extreme slomo followed by a jerky catch-up movement where a few seconds worth of frames are lost. When I check with CtrlAltDel, the CPU workload meter is pegged at 100% as soon as flash player starts.
The computer isn't that slow (AMD athlon 64 processor, 2.2 GHz, 2 GB RAM, with WinXP installed). The error appears in Firefox as well as in a current version of IE. The problem does not appear in HD videos playing from the hard disk either in my preferred VLC player or in WMP. The download rate isn't a problem either, as I am on a 16,000 kbps VDSL connection. Oh, my relatively recent Acer notebook (TravelMate 5730, Intel Core Duo 3.93 GHz, 2.92 GB RAM, running Win XP as well) is running smoothly as well.
Do I have to get a new machine simply in order to watch a bit of Craig Fergosun HD the HD timleapse movies Phil Plait posts on his site? God, does that suck.
Help, anyone?