Tweak Tester.

[maxping]

Tweak tester

The tweak tester analyses a sample of data and can tell you, among other things, what your MTU and RWIN are and whether or not you are blocking PMTUD. Changing these settings can sometimes speed up your connection.

http://www.netmonitor.org/tools/index.php

[Rik]

In addition to which, I'd suggest going to SpeedGuide and check out their analyzer and optimizer options, followed by their speed test.

[Alex]

Mine says: "Retransmitts detected, indicates a problem".  Huh? 

[Rik]

It usually means you're using too high an MTU, Alex. Assuming you're on 1500, try reducing to 1458, adjust RWIN to match.

[Alex]

How do i do this?

[Nerval]

You're a brave man Alex   

Follow This.

[Alex]

Cheers.