The second site is only checked if the first site fails. If I were to guess the reason for the slowness I'd say it's because you have some firewall or internet problem. Because wyUpdate checks for updates to itself by downloading a file on wyday.com. So if you have a block on internet (or on our site) then this will slow down the checking process.
Read here about hosting wyUpdate on your own site: How to make a custom version of wyUpdate.