It may not help but I notice the same complaint about slow Internet speed in the evening with every ISP/RSP. The slow speed in the evening seems to be for almost all users and all ISPs. If you are on NBN FTTN with 384 subscribers per node with a 2Gbps link back to the exchange and who knows what back to the point of interconnect, then 2000Mbps divided by 384 = 5.2mbps each. Now not all households will be using the Internet at the same time but many households have more than one device connected to the Internet. However if 21% of subscribers decide to stream 4K Netflix in the evening then the capacity of the note is exceeded with nothing for the other 79%. See [url]
http://blog.jxeeno.com/poor-nbn-fttnb-d ... ongestion/[/url] for a commentary on this.
So bottleneck number 1 is the capacity of the node and it doesn't matter if you pay for 100/40, as it can't be delivered during peak hour just like you can't drive a 350km/h Ferrari through Sydney or Melbourne streets during peak hour.
If you have FTTP then you are better off because the connection between you and the exchange is shared with considerably less other subscribers (I can’t find the figures but from memory it was only 32).
ISPs/RSPs like Exetel buy bandwidth from the NBN. I saw a figure at [url]
http://rogermontgomery.com/nbns-major-issue/[/url] of $17.50 for 1Mbps of bandwidth or $437.50 for 25Mbps which Exetel resells for $49.99 so ISPs oversubscribe or share that between customers hoping that not everyone will be downloading simultaneously which is the case with regular browsing and the occasional download. However when people stream movies or all turn their computers on after Microsoft issues a 3GB update to Windows 10, then major congestion, just like the M5 in Sydney during peak hours. So bottleneck number 2 is the ISP balancing their retail budget with high charges from NBN spread over many customers. If you want 100Mbps 24/7 then expect to pay a lot lot more like corporate customers do. You can get that from Exetel for $1,350 a month.