Lets put you guys to the test because I have no f***ing clue how to fix this. Honestly, the PCI-E card may be the only way that it could work as it has nothing to do with the I/O portion on the back.
This started on Thursday, June 7th where I was starting to get half of my download speed on my desktop. Thought rebooting the router and the modem would fix it, but no. Even after everything I've done (listed below) I still have half download speed on my desktop, but my upload is normal. To preface, I have Windows 10 Pro, I didn't do any recent updates for my computer when this happens. I barely update and reset my computer as is, so updating wouldn't be the issue.
- Rebooted router and modem several times, including leaving them off of power for at least 5 minutes, half speed.
- Comcast came and checked all my connections and made sure everything was working as it should be. Hell, the guy gave me faster internet speed than before, half speed.
- Replaced the router with a faster and better one, half speed.
- Replaced the Ethernet cable going from my router to my desktop with a brand new one, half speed.
- Laptop using WiFi, direct LAN port and USB Gigabit adapter to both the modem and the router give me max speed.
- Phone/WiFi was giving full speed before and after the new router.
- Switched ports on both the old router and the new router with both the old and new Ethernet cables, half speed.
- USB Gigabit interface gives me half on my desktop but full on my laptop with connected through the router.
- Updated Windows fully to see if that was a reason, half speed.
- Ran the speed test with everything updated, but with all other programs off on my desktop, half speed.
- Tested it with the firewall off, half speed.
- Tried disabling IPv6 on my NIC card, half speed.
- NIC is running in Gigabit Full Duplex mode.
- Updated NIC drivers. Even uninstalled the drivers fully, then reinstalled them again. Half speed.
- Ran Malwarebytes and found nothing.
- I have a PCI-E Intel Gigabit NIC on the way and it will be here Tuesday so I will test that out but I'm not expecting it to be any better to be honest.
- The only thing I can think of that actually updated on Thursday was Steam and as I said before, I would get the same issue with it on and off.
- Did Speedtest on both Edge and Chrome.
- Tried the USB Gigabit adapter on a front USB port to see if getting away from the back I/O would work and nope, half speed.
So I am at the end of my rope for the most part. 300 Mbps is what I should be getting on this system but I'm generally getting between 130 and 150 on this desktop while everything wireless in my home gets close to or at 300 Mbps. The fact that the USB Gigabit device and on my onboard gigabit work the same way on my machine makes me think it's either something with my motherboard and its chipset, or it's something with Windows. Any and all advice would be greatly appreciated.
PS - My upload is about 11/12 Mbps on both this desktop with the issue and on my laptop/phone.