Steam downloads crawl while everything else is fast

change the download region. steam settings > downloads, it picks a server automatically and sometimes picks a bad one. try a nearby city that isn't the default and see if speed jumps. clear download cache on that same page fixes some weird slowdowns as well. it logs you out of steam afterwards, so have your login handy.

300mbps works out to about 37 MB/s, so yeah 2-3 is really slow. Check Steam's download settings for a bandwidth limit, it's easy to have set one and forgotten. Then watch the graph on the downloads page: if the disk usage line is pinned while network sits low, the drive is the bottleneck, not your connection. Steam has to unpack and write everything, so an old hard drive or a nearly full one drags it right down. Antivirus scanning the steamapps folder does the same, try excluding it. And if you're on wifi or a VPN, test on a cable with the VPN off just to rule it out.