My TPG conection has been been going fast and slow for the last 3 months. At the moment it is good but at times it slows to dialup speed. Mine can be good for weeks and then slow for days, really frustrating. It is almost like telstra is sharing my conection with someone else? I have tested / replaced everything and my problem is with the lines. Sometimes my net will go faster if I unplug the phone. Copper wires, dont you just love them...not, and the last telstra tech told me it would be at least 5 years before the NBN is available in my street (or never if the current gov has its way)
You can test your conection here
http://www.tpg.com.au/support/speed_test.php
Good luck