When it 50Mbs not 50Mbs? When you subscribe through Time Warner.
We subscribe to Time Warner's 50/5 service, which should give us download speeds of 50Mbs and upload speeds of 5Mbs, or something close I would think. We consistently see download speeds in the 3Mbs to 15Mbs range, which is completely unacceptable. A call to Time Warner provided us with the URL http://speedtest.nyc.rr.com/ which is a speed test hosted on the on the NYC backbone (I am sure that they have them for other cities as well). Interestingly, running the speed test shows pretty consistent results in the 40Mbs to 50Mbs range when run at the same time (well not really the exact SAME time) as tests against other speed test providers that are returning significantly lower numbers.
Some people see these results and think that Time Warner is gaming the system to make themselves look better by cheating on their speed test (there is a YouTube video that "proves" exactly this). I don't think that this is the issue. I think that it is more likely that the Time Warner network has bottlenecks at it's peering points with other networks. What does this mean? Well, if you are connected to Time Warner and are trying to reach someone that is connected to Level 3 (another provider), somewhere there has to exist a connection between Time Warner and Level 3 (and it's all these connections that make up the Internet). That connection is called a peering point. Sometimes two networks are directly connected, sometimes data has to route through a few networks to get to the desired network. Typically the better peering a network has (direct connections to other networks), the better the service and the more expensive the service because peering is expensive.
If the Time Warner speed test is performing well, but another speed test is not, chances are that there are congestion issues somewhere between the Time Warner network and the network hosting the other speed test that are causing the poor performance. Knowing this does not solve the problem, but it does provide the information that YOUR internet connection is fine and that it is really just a function of the Time Warner network and short of them upgrading their peering, or your waiting for less busy times of day, the only real solution is to change providers. Unfortunately, that is not always an option.
Oct 17, 2011 UPDATE: I upgraded my iPhone from iOS 4.x to iOS 5.0 and the Credential did not change. So now it is a complete mystery how the Credential ID on my phone and the Credential ID that Network Solutions had were different.