Global Name Catching - Ie .com's

[transcom]

With Nominet and other registrars that use DAC / EPP , we can hit the DAC server at a rate of 432000 within a 24hr period or a max of 1000 times a minute

Does any one know if US based registrars have a similar access rate or is it all limited by API calls through a third party ?

Cheers

Bill