Slow WiFi on new PC build - bad motherboard?

[ShredHead]

I've just helped my friend build his first PC. The build was a success, everything benchmarks perfectly, however the WiFi is having serious issues.

 

The first time we booted the internet connected just fine (no tests were done, but it seemed slow) and we downloaded the drivers and BIOS updates to get everything to the latest version. Once that was done we noticed how slow the internet was and did a speed test that came back 0.7mb down and 3.5 mb up. It's supposed to be 60 down and around 5 up and his phone tested pretty close to this. Also, when the PC is connected it makes other devices test slow so we're seeing >1 download speeds on the phone and on a laptop. Turn off the PC, and speeds go right back up.

 

So, here's what we've done so far. We uninstalled/re-installed the network driver, no improvement. We updated Windows (slowly) and he tells me for a while it seemed to be fine. Then he see's a new update for windows (I'm assuming the latest update) and after that his speeds were slow. This is where we are, debating wiping the drives and fresh installing windows.

 

specs

Ryzen 7 1700x

Gigabyte B450 Aorus Pro WiFi

Corsair Vengeance RGB 3000mhz

MSI Gaming X RX580 8G

240gb SSD

1TB HDD

Corsair RM550x

[ShredHead]

should also mention we tested Ethernet, it is also slow.

[RobbinM]

Have you tried resetting the router?

Is the new PC on DHCP settings?

[unsungheroist]

also reset your modem. easy way is unplug it for a few seconds and plug it back in.