I have Road Runner Turbo and the speeds as of recent are very inconsistent. I'm paying for 20Mbit/2Mbit.
I had a cable tech check the signal and it was fine, they even replaced my modem.
Still, sometimes I'll get 2Mbit down, sometimes I'll get 20Mbit down but mostly it's around 5-8Mbit. I'm using »speedtest.cfl.rr.com
I've tested with a computer directly connected to the modem. With a computer wired to a router. With a wireless connection.
Each method has shown that sometimes it maxes at 2Mbit, sometimes at 20Mbit but mostly at around 5-8Mbit.
I just took 5 speedtests within 2 minutes of each other... same configuration, first one was 5Mbit down, second one was 10Mbit, third was 13Mbit, fourth was 18Mbit, fifth was 5Mbit.

Any ideas what the problem might be so I can figure out what to test or who to call and what to tell them?