Flash only runs on a single core, and most Atom's have the same processing size as a core on my Core 2 (1.66ghz x 2). This means any very intensive flash will still max out a processor, which is why flash urgently needs to implement hyperthreading to alleviate this process, until it does it's in risk of replacement in some areas of its market.
You clearly have no idea what you're talking about re: concurrency. If mentioning cores repeatedly (and summing their clock rates) wasn't enough of a giveaway, proposing Hyperthreading in userspace is just hilarious.
The problem with flash is not that it's single-threaded -- it's because NSAPI plugins run in (and block) the main() thread!