We recently switched to AT&T after having Time Warner's Roadrunner for 10+ yrs. I chose the middle of the 5 speed choices, thinking it would suffice. I couldn't believe how sllllloooooowwwww it was! But I didn't have time to call them to find out if there was anything they could do to fix it. Finally, after a month my husband called. The tech came out and ended up pushing in the 'reset' on the back of the model or maybe it's a router - sorry! I'm not computer saavy. Anyways, now it works just as well as the Roadrunner! And we're happy campers! Maybe your problem is something just as simple
