fullpacodd

I've got UPC fiber power broadband which is 200 mb/s and my PC has a really decent internet card to support 200 mb/s it can support up to 500. But lately I have noticed that there is something on my PC that is limiting my download speed when or when not downloading something.
It drops to as low as 3 mb/s when idle and when downloading something it slowly builds up (very slowly) instead of it downloading at it's full 200 mb/s and I find this really annoying, I've tried disabling firewall and my antivirus but neither worked. I need to know if there's some third party software limiting it because my laptop gets all 200 mb/s so it's not the provider or my location because I'm connected via Lan.
Thank you.