I upgraded to 600 and all I get is like max 150 mb/s upload speed. And it’s even worse when I use an Ethernet cord. It seems better on wifi but still inconsistent.
Sounds like you need a little troubleshooting and optimization. Particularly concerning is 150Mbps down over Ethernet. I would grab a coffee, call Shaw and settle in for some tech support. Don’t rule out a new cable router either. Ask for a Technicolor. I have found them to be better than the “other” one.