Capped at no more than 8.4 MB/s for some reason with WOW. Comcast would go up to 20 sometimes (on the speed test only. I could rarely watch a YouTube video without it buffering, or download one MP3 in under 3 minutes.), even though I had a 6 MB/s plan. Comcast was the flakiest service I ever had. When we moved and got WOW, I havn't been happier. It's good enough for me.