Slow download speed on Windows 10

Question

When I built my computer I only had a Windows 7 disk lying around, so I installed Windows 7; Internet worked completely fine and didn't have any issues with the download speed. I then downloaded Windows 10 onto a USB stick and ran a fresh install (since I read that upgrade installs can cause problems); the first time round the download speed was fine, but now my download speed is incredibly slow.

This doesn't seem to be related to a current ongoing problem with the motherboard as Internet worked fine in Windows 7.

On testing the speed, I found that I get a maximum of 3Mbps download and 0.96Mbps upload:

The Internet connection is rated at a maximum of 20Mbps download and 1Mbps upload; it seems that while the download speed has been impacted, upload speed is not. When I download anything, the entire Internet connectivity of the machine is bottlenecked by the program doing the download; this doesn't usually happen as my router's QoS prevents this from happening.

Thinking that it was a driver issue, I reinstalled the driver for the Ethernet (Intel(R) 82576 Gigabit Dual Port Network Connection) with no effect. I then downloaded and installed the driver for my motherboard from the manufacturer's website, again to no effect.

I read that disabling “Large Send Offload (LSO) could fix the problem; I have done so but yet again, to no effect. I've also done the standard stuff of rebooting the router & verifying the speed with another Ethernet device.

I also ran a speed-test on my phone, and it's the normal speed (so the router or the actual Internet connection isn't the issue here):

There are also quite a few settings in the Ethernet adapter's properties; perhaps one of these could be the cause?

The settings are as follows:

• Interrupt Moderation : Disabled;
• Jumbo Packet : Disabled;
• Large Send Offload (IPv4 & IPv6) : Disabled;
• Locally Administered Address : None;
• Log Link State Event : Enabled;
• Performance Options :
  • Flow Control : Rx & Tx Enabled;
  • Interrupt Moderation Rate : Adaptive;
  • Low Latency Interrupts : Disabled;
  • Receive Buffers : 256;
  • Transmit Buffers : 512
• Priority & VLAN : Priority Enabled;
• Receive Side Scaling : Disabled;
• Receive Side Scaling Queues : 1 Queue;
• TCP/IP Offloading Options : None Checked;
• Wait for Link : Off

Answer 1

Turns out that this issue isn't driver-related at all; rather, it is related to a combination of the powerline adapter I'm using and the actual plug socket.

Someone told me that a high load can disrupt communications for PoE adapters, and that seems to have rung true in my case; the issue can be tracked back to when I first started gaming with the machine. However, the 362W maximum output should not be high enough to disrupt PoE communications; therefore it can be determined that the PoE adapter is faulty.

The combination of the 'high' load and faulty PoE adapter led to a disruption in the PoE adapter's communications.

Since the PoE adapter is faulty, my solution is to RMA it for warranty replacement. TP Link's warranty page states that:

If you are experiencing product defects within the warranty period, please FIRST contact the online/retail store where you originally purchased the product(s) to ensure a rapid replacement.

Therefore I'm contacting the original retailer for an exchange/replacement, which is Amazon.