Choked up backbone??? I've seen my upload better than down load at times I believe due to extremely overloaded backbone connections..
Guess it could also be the speed test server, but the slow speed to other sites, when it occurs, would tend to indicate a congested backbone link..
It will vary depending on the location of the speed test server I'm testing with..
1/4 mile long wire DSL connection on my end always has rock solid, consistent S/N, therefore not an issue.
Recently experienced a period of this and then it went away...
btw.. highly recommend Visual Route Speed test as it shows throughput over time versus the peak attainable speed that many speed test sites give. If you use this test, be sure to click on the "test results" link for detailed info about the connection over time.
»myspeed.visualware.com/s ··· ware.com
I like their test method so much that I bought their app "My Connection PC" that gives even more information about the quality of the connection.
»www.myconnectionpc.com/i ··· dex.html