Slow Download Speeds on LAN

[Rickman]

Hi guys, I was hoping for a bit of help with this annoying issue I’m having.

I have a Dell PC running OPNsense with an Intel I350AM2 double NIC PCI card for LAN and WAN.

Speed tests for my connection are fine, they’re reporting down speeds of 200MB/s, which is correct.

The problem I’m getting is very slow download speeds, but just on the LAN connection. I have a VLAN setup for Wi-Fi and downloading the same file wirelessly is fine.

On the physical LAN subnet, downloads start off about 200kb/s, then decrease to nothing very quickly.

I even wiped, installed and set up OPNsense from scratch to see if that helped. It worked for a day or two, then back to the same slow download speeds.

Browsing the internet is fine, it just seems related to file downloads.

I have hardware offloading disabled, although I did try enabling it but no change. I’ve also tried setting the MSS value to 1300 I’ve seen mentioned before, that doesn’t help either.

Does anyone have any ideas what might be causing this?

Many Thanks