Every time I reboot my modem, there is no freeze and everything works very fast. But after like a day or so, I start getting a "freeze" right before each page loads, which I am assuming is DNS. The Macs on display in the Apple store don't have that "freeze", so I'm assuming it's the ISP (Comcast)? I don't think it's a line condition either because my modem signal levels are good. Is this DNS or something else?