Why is Windows 10 networking so poor/slow?

[Rainmaker]

My desktop (see sig) runs Windows 10 out of necessity because a couple of apps I need still aren't cross-platform. I have Kaspersky Antivirus 2017 running, Defender disabled and Windows firewall disabled. The local network is set up like this:

VM 200/20 (SuperHub3) > pfSense (APU2C4) > Ubiquiti UAP AC PRO

The desktop currently connects via a PCIe wireless AC card (TP-Link Archer T9e AC1900), and syncs around 1.0 to 1.3 Gbps. Although multi-threaded downloads like Usenet will max the line more or less, most stuff is quite a bit slower. For example using curl to grab a 100MB test file from cachefly, under Windows 10:

$ curl http://cachefly.cachefly.net/100mb.test > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  100M  100  100M    0     0  10.8M      0  0:00:09  0:00:09 --:--:-- 10.8M

Then the same test under Debian Stretch virtual machine on the same desktop machine, using the same wireless card etc:

root@stretch-vm:~# curl http://cachefly.cachefly.net/100mb.test > /dev/null

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current

                                 Dload  Upload   Total   Spent    Left  Speed

100  100M  100  100M    0     0  26.0M      0  0:00:03  0:00:03 --:--:-- 26.0M

Although it's more than usable day to day and heavily multi-threaded downloads spool up OK, clearly Windows 10 is rather lacking compared to Linux, even in a VM within the Windows host (ironic). Torrents also tend to cap out around this speed (~10MB/sec) even things like Ubuntu 16.10 Desktop, which will saturate the line via Linux using the same torrent client.

Does anyone have any bright ideas on speeding things up towards something close to parity between the OSs? I thought the days of tweaking Windows for things like this were over.

 

[Rainmaker]

To verify you're actually seeing slower network speeds I'd start by using a much bigger file to give your transfer speeds a chance to settle down, a 3 second window of transfer is way too short to measure with. I'd also try it first over lan, then compare results with wan.

To be fair it's 9 seconds. It was Linux that downloaded it at full line speed instantly, giving a 3 second total transfer time. Windows took 9 seconds and still didn't even reach half the available line speed. As I said torrents and other downloads seem to cap out around the same speed on Windows, hence using curl to a known fast test file to double check. If you know any 1GB files on similarly fast servers let me know, though, because I've been looking for one. Cachefly is a CDN with huge (HUGE) bandwidth worldwide, so they always give linespeed where possible.