It’s not all that weird to come across Facebook stealing CPU and Virtual Memory like it’s an aggressive cancer that wont give up.
It’s mostly due to all that flash and, depending on the time of the month/year, if they’ve updated some element in the interface. Then it’s flash + poor coding that can cause this hogging behavior. That’s not to say browsers couldn’t be designed better, ahem.
Anyway – when you run into the slow browser check your processes. There’s a big chance Facebook is at the root of the problem. The only fix is to restart your browser. Yes FBWatchdog is and has always been one of those, “Flash is the bane of the internet” types. Why? Because it’s true.