Slow port 80, rest fine. Only on one device in house.

I'm having an issue where on my desktop port 80 runs very slow. Often websites will fail to load, or only partially load. I've tested directly to my modem, and with my router; the issue persist. Also when pinging websites I get results of around 180ms, but no packet loss. Normally I see around 16-32ms.

However, on my mobile phone desktop and mobile version websites load instantly, as expected.

(EDIT) Malware/virus scans are complete and have come back clean.

The problem has come and gone over the past couple weeks, but more recently it's been so bad I cannot even browse anymore. Realizing it was only port 80 being affected I decided to go through my VPN to test web traffic; sure enough, smooth as butter. Slightly slower because of the VPN, but everything was working perfectly.

Here's what I've done so far to try and correct the issue:
- Virus/Malware check.
- Tried various DNS servers such as Google or OpenDNS.
- Factory reset on router and modem.
- netsh winsock reset

Any thoughts?

Figured it out. The DNS settings for IPv4 were set to that of my VPN, even with the VPN off. Set to automatic and problem resolved.