Ethernet cable much slower for PC than any other device

[Swift_1]

My PC is connected to the router via an ethernet cable, but has been experiencing an extremely slow download speed.
The router is a BT Hub.

Every other device connected to the router gets about 30-40 download, with another PC that's connected to the router via ethernet getting about 45+ download. However, my PC is getting around 6 download consistently.
It started about 4 days ago and I even tried to rollback my system to before that date and still, nothing changed.

Strangely though, the PC still gets about 7-8 upload - The same as every other device that's connected. It only seems to be the download that's affected and for only this PC.

I've tried swapping out cables to make sure it wasn't a damaged cable (Even pinging the router with both cables to check for any packet loss).
I've tried updating the network drivers in device manager. Still nothing.

I don't know if any kind of malware could cause something like this to happen?

Not sure what else to try.

 

[webworkings]

Well, there could be a few factors here. 1. How many devices are using that router/modem? The more on it, that are running at the same time, the worse the speed will get. 2. Are you sure whatever program you are using to check the speed is giving you the right info? You should be able to log into your modem on the computer and check the speeds there. 3. The port you are connecting through is having problems so it is giving you worse speed (less likely that any others, but can still happen).

Personally I would look at the number of devices and what they are doing as the cause. The more intense the things being done, the worse the speeds you will get will be. So if you have two others watching say movies or playing graphic intensive online games, or downloading a lot, at the same time you are trying to do something, the speed can go poof. You should be able to, from inside the router/modems settings, set it up to give certain devices priority, set access limitations, time limits, etc. Also, if you have your WiFi active, be sure to check that no outside source is accessing it, putting further strain on the resources.

 

[Danra]

Check for a virus, if there is none and if no one is sharing your router you may need to purchase a new NIC. If other computers or devices are using the router, disconnect them and check your speed again.