On my other more powerful systems I am a quite happy user of Firefox, however on this 12-year old Pentium II 233MHz with only 156MB RAM, Opera seems to work best. Midori crashes from time to time. Firefox is too CPU hungry and Chrome just does not want to start.
Adobe Flash works with Opera, but it just takes too much CPU resources to leave it enabled on this machine. This does not surprise me: Adobe Flash has become such a bloat-ware thing that even Steve Jobs does not allow it on iPad.
However, there exists such a thing as Adobe FlashLite that runs on ARM processors. See: http://en.wikipedia.org/wiki/FlashLite
Chumby and others use it: http://www.chumby.com/pages/learn_overview
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