Why internet speed dropped on one device

Internet Speed on One Device Can Drop for Many Reasons, Even If Other Devices Work Fine

Based on your actions, the problem is clearly related to your PC, and the motherboard can indeed be one of the possible causes.

Table of Contents

• Main Reasons for Speed Drops on One Device
• Motherboard Issues
• Additional Possible Causes
• Diagnosis and Solutions
• Conclusion

Main Reasons for Speed Drops on One Device

Internet problems on a specific device while others work normally are usually related to local factors. According to research, the main reasons include:

Network Equipment Issues:

• Outdated or damaged equipment - old network cards and routers may not support modern connection speeds [source]
• Poor network cable connection - due to a loose latch or damaged connector [source]
• Network controller failure - especially common on motherboards with integrated network adapters

Network Configurations:

• Wireless connection principle - can reduce initial speed by 10% to 90% [source]
• Poor driver compatibility - especially between different Wi-Fi hardware manufacturers [source]

Motherboard Issues

The motherboard can indeed be the cause of internet speed drops, and your symptoms point to this as a possible cause:

Signs of Motherboard Problems:

• BIOS/UEFI settings may limit the network controller’s bandwidth
• Physical damage to contacts in the network cable slot
• Issues with the Realtek network controller (very common in modern motherboards)

Important: Research shows that motherboard network controllers often become a “bottleneck” even with fast internet [source]. This is especially true for boards that support 1000 Mbps speeds but work slower due to software or hardware limitations.

Your Specific Situation:
Since you’ve already replaced the network card, reinstalled Windows, and updated drivers, but the problem persists, this really indicates a possible motherboard failure. Based on your description, the video card issues that disappeared after reinstalling Windows could also have been related to motherboard failure.

Additional Possible Causes

Driver and Settings Issues:

• Realtek Lightweight Filter - components that can artificially limit speed to 10 Mbps [source]
• Forced low speed setting in network interface properties [source]
• Memory leaks in drivers - as described in one case, the driver could have internal errors [source]

Software Limitations:

• TCP/IP stack in Windows may be corrupted
• Background processes may consume bandwidth
• QoS settings or bandwidth restrictions

Hardware Conflicts:

• PCI slot failure on the motherboard
• Power issues with the device
• Electromagnetic interference inside the computer case

Diagnosis and Solutions

Step-by-Step Motherboard Diagnosis:

1. Check Cable Connections:

   • Ensure the latch in the network cable slot is not broken
   • Verify the reliability of the cable connection to the port [source]

2. BIOS/UEFI Settings:

   • Enter BIOS and check network controller settings
   • Make sure the network port is enabled and operating at full speed

3. BIOS Update:

   • Check for BIOS updates on the motherboard manufacturer’s website
   • Updates often include improvements to network controller performance

4. Additional Network Card:

   • Use an external USB network card for testing
   • If speed normalizes, this will confirm the motherboard issue

Additional Checks:

# Check current network settings in Windows (PowerShell)
Get-NetAdapter | Select-Object Name, InterfaceDescription, LinkSpeed, Status

Solutions for Motherboard Issues:

• Disable “Realtek Lightweight Filter” components in network interface properties [source]
• Update the network driver from the official motherboard manufacturer’s website [source]
• Check speed and duplex settings in Device Manager
• Try resetting network settings through Command Prompt

Conclusion

Your situation really indicates a possible motherboard failure as the cause of internet speed drops. Based on the symptoms described and your troubleshooting attempts, this is the most likely cause.

Key Takeaways:

1. The motherboard can be the cause, especially if the network controller is integrated
2. Video card issues at the same time also indicate hardware failures
3. Replacing the network card and reinstalling Windows ruled out software causes

Recommended Actions:

• Check network cable contacts and the slot on the motherboard
• Update the motherboard BIOS
• Use an external network card as a temporary solution
• If motherboard failure is confirmed, consider replacing it

Even if the problem isn’t the motherboard, these steps will help accurately determine the cause and restore normal internet operation.

Sources

1. Why Internet Speed Suddenly Dropped: Typical Causes and Their Solutions
2. Why Internet Speed Drops and Can It Be Fixed
3. Low Internet Speed on PC
4. Does Not Deliver 1000 Mbps Speed, Despite Resources Allowing
5. Why Does Internet Speed Decrease When Connecting Through the Motherboard?
6. Internet Speed Not More Than 10 Mbps When Connected Directly
7. Windows — Cause of Slow Internet
8. How to Fix Cable Network Issues with Motherboard
9. What to Do If Internet Speed Dropped: Causes and 10 Practical Tips
10. What to Do If Internet Speed Suddenly Dropped?