It could be where your from and the connection to the site. Run a ping against this website and let me know your results. All most speedtest sites do is run the test against a server closest to you so that you can get the best speed.

An example, I'm from Scotland, UK. If I run a speed test against any UK server I get 50MBPS down and 5MBPS up and a 45MS ping. If I run it to a random East Coast server (NY) I get 30 Down and still 5 up but I get a 97MS ping. This would mean I would have a second of lag between clicking and loading.

Running a ping on this site and I get 130MS Ping, which means it takes 1.3 seconds between me clicking, the site receiving it and me getting the result.

And I'm trying to keep this as simple as I can, I don't know your IT experience so hopefully it makes sense.

To run a ping, open up command prompt (Start, Run, type CMD, press enter. Or if on Vista/7, search for CMD and click it). Type without quotes "Ping guitartricks.com" and then post the output here and I'll let you know what it means :-)