In reply to a post by danielhyde:

The WD15 dock he has tried is Thunderbolt

Good to know!

I did do a bit of follow up reading after your message, and so I tried disabling the Killer Wifi device through BIOS and deleting all instances of the programme, drivers, registry entries etc. that could possibly be causing it. Nothing different.

Alas, I just have to accept that some software is throttling me. Unless I do a fresh install, the proverbial needle and haystack come to mind as my completer knowledge is pretty limited.

"It's not a huge problem as real world downloads from Steam etc. I can usually peak out at 100 MB/s and it doesn't affect me for work."

800 mbps doesn't seem to be throttled.