Internal connection between two PCs seems to max at 50 MB/s

[King Mustard]

PC (wired)

• On-board Realtek RTL8111H Gigabit NIC (2014 model)
• Wired directly to a BT Smart Hub 1 802.11ac wireless router
• Windows Settings shows a link speed of 1000/1000 Mbps

Server (wireless)

• Addon XWP3000R 802.11ax wireless NIC
• Latest Intel AX200 drivers (v22.40.0, dated March 2021)
• Wirelessly connected to the BT Smart Hub 1 wireless router
• Windows Settings shows a link speed of 866/866 Mbps
• Appears to have full wireless signal strength

When I transfer files from the PC to the server, the speed varies between roughly 30 MB/s and 70 MB/s (very variable, even during the same transfer).

When I transfer files from the server to the PC, I get a constant 47 MB/s transfer speed. I was expecting (hoping?) for around 120 MB/s (Gigabit).

Any ideas?

[Apex]

You won't see 120MB/s, the server is connected over wireless for a start with a link speed of 866Mbps,which is 108.25 MB/s at the top before anything else is taken into consideration.

The only way you will get a consistent speed is with the server hardwired; wireless will never give you that by its very nature (and it doesn't matter how quick your wireless is).

Wireless is ok for burst traffic but for long constant transfers it will never match a hardwire setup.