Imho the survey should be protected behind Phoronix.com login system. One survey submission per login. Select only the answers you feel most strongly about.
Phoronix is pretty decent against the automation of new account creation because of the CAPTCHA, so if somebody wants to sit there all night and do 50 surveys by making 50 gmail accounts and putting in the phoronix CAPTCHA for each one, let 'em. They'd also have to use some mechanism to keep changing their IP address, since phoronix should already have a limit on the number of accounts you can register on a given IP address per 48 hours or so.