Edu versus Speakeasy Speedtest

I work for an Edu with multi-gigabit Internet connectivity and I get questions from users saying "Why am I only getting 14Mb when I run this speed test?" I have got to believe that the various Internet speed tests (Speakeasy or dslreports) are rate limited to prevent someone from shutting them down. I am able to get 300-400Mb running from a PC inside my network to NDT servers located on Internet2, so that tells me my border and internal network is healthy. Can someone on this list shed some light regarding reliability and accuracy of these various speed tests especially for an Edu with lots'o bandwidth? Thanks. Bill Murphy University of Texas Health Science Center - Houston