I am posting this purely for the benefit of others ... and I would hope also that TPG Support will make a note of this and put this into the TPG Support Knowledgebase!
I just upgraded yesterday from NBN12 to NBN50 and was keen to check out the improved performance, so imagine my disappointment when I found I was getting just 10Mbps Download still. Odd thing though, was that the Upload was nearly 20Mbps. What? Clearly NBN50 was in play, but not for downloads.
Did a HUGE amount of testing, spoke with TPG Support, we eventually discovered that other computers on my home network were happily downloading at 45Mbps. Why not MY laptop? I checked the cabling path, switches, router, modem, nope, no joy. Made no difference whether using ethernet cable or WiFi.
Then I tried using the iiNET Speed Test (https://www.iinet.net.au/internet-products/broadband/speed-test/) and got 45Mbps. But with SpeedTest.NET (www.speedtest.net) just 10Mbps. What the ... ???
Alright, I know that NBN50 is working ... hmmmm ... lots of Googling and newsgroup reading ... resetting the TCP/IP Winsock stack. fiddling with Receive Window AutoTuning ... nope ... nada ... no joy ... and then I finally found the cause, thanks to some other Dell users who'd had the same issue.
Uninstall a bit of Dell-supplied software called SmartByte from my laptop. Immediately I am getting 45Mbps. Thanks Dell, thanks SmartByte, thanks a LOT, you just cost me half my Saturday day off!
Thanks for dropping by and for the information you've shared. This would definitely help the community whose speed on specific computers have been slowed down due to the SmartByte software.