Is a Q9550 substantially better than a Q9400 for running FSX?

The Q9550 is about £40.00 ($65.00 US) more expensive, which doesn't seem too much if the difference is really noticeable. If it's not, I'd rather go for the budget option. What do you think?

My MOBO is an ASUS P45QL/EPU with 4GB 1066MHz DDR2. GPU is probably going to be a 9800GTX

Thanks for any comments.

$65 does seem a bit high for the 5-10% performance you'll gain with the 9550.

Well, that's the info I've been looking for. If it's only a question of a max 10% better performance, I'll go with the Q9400. Subjective views on various forums give the impression that the Q9550 is streets ahead..

Thanks