Slow download speeds, brand new PC W11

[Razordoll]

Hello, so I'm having a odd issue.

My 10 year old system, is sitting here, same internet & same crucial SSDs, just running windows 10 & it can download at 300+Mbps.

My brand new considerably more powerful brand new PC, running windows 11, & I start off fast downloading, but after 10 or 20 seconds or so, the download speed starts to slow down until eventually it hits the 40-60 Mbps range.

I've run all sorts of tests, I've tried the steam_dev.cfg fix, I've tweaked my windows settings, every fix I can find googling, I've tried & nothing is working & its starting to frustrate me.

I am literally downloading to the exact same crucial SSDs that were in the win10 system (they were my game drives, I moved them from the old system to the new system), & I also have a new nvme drive that is my new primary drive for the win 11 machine.

I get FANTASTIC speeds in windows 10, but windows 11? just the pits!

I'm at a loss here how to fix this. Can anyone help?

Thanks in advance =)