I am a trifle confused as I just did a speedtest and got the result given below.
Looking a the modem configuration shows
Primary Downstream Service Flow SFID 73056
Max Traffic Rate 337920000 bps
Max Traffic Burst 10000 bytes
Min Traffic Rate 0 bps
Primary Upstream Service Flow SFID 73055
Max Traffic Rate 16128000 bps
Max Traffic Burst 16320 bytes
Min Traffic Rate 0 bps
Max Concatenated Burst 16320 bytes
Scheduling Type Best Effort
http://www.speedtest.net/my-result/4285367251