My results from Speedtest.net always tend to be higher than the results from testmy.net. I've been calling and complaining about my Internet 200 (200 Mbps down / 20 Mbps up) package, because I've been getting consistently 150Mbps or slower with my connection, even with Speedtest.net. And my uploads speeds are around 1 Mbps (should be around 20Mbps). The only time my service is awesome is when a service technician comes out to inspect my line and setup. I have had about 12 services calls in the last 6 months because the speeds have been getting worse. I have been using an SB6141 modem and then upgraded to a SB6183. Before the issues kicked in Speedtest.net and Testmy.net both would show I was getting 220-240+ Mbps on the SB6183, the SB6141 would struggle to hold onto 200 Mbps. One service technician explained that Mediacom will allow direct connections to Speedtest.net sites while the majority of web traffic will be routed through their servers. The utter definition of an internet fast lane. This was the only technician that charged me for a service call too. That charge was dropped when I called customer support. You're seeing varied results between Speedtest and Testmy because Mediacom providing you with a direct connection to certain speed testing services. I also have found that with Testmy.net, if you do a manually test with a 100-200MB package size, then it will provide better results. This is because the packages you download from Speedtest.net are around 200MB too.