The question about LAN speed fluctuations between 2.5Gbps/100mbps and 10mbps is being addressed.
The question about LAN speed fluctuations between 2.5Gbps/100mbps and 10mbps is being addressed.
A few months ago I assembled a PC
PC Specifications
Mobo: MSI PRO B650M-B
CPU: Ryzen 5 7600
RAM: 16GB
Storage: 1TB SATA SSD
PSU: 650w
Because the non-WiFi motherboard required a USB network adapter, everything functioned properly, but I encountered issues with LAN speed. I also tried connecting the PC using a LAN cable, expecting higher performance. However, it only provided 10Mbps. I adjusted the speed and duplex settings to 2.5Gbps full duplex, but the speed automatically reset to 10Mbps.
I suspected the LAN cable was defective, so I replaced it with a new one that met the same Cat 6e standard, but the issue persisted. I continued experiencing only 10 Mbps regardless of changes.
After removing the cable from the PC and connecting it to my gaming laptop, I discovered the laptop achieved stable speeds using the same LAN cable (indicating no cable defect).
I still believe the problem lies within the motherboard, though I took the PC elsewhere and connected it with a LAN cable, where it performed well at around 100Mbps.
Now I’m unsure what is truly causing the issue. The motherboard seems fine, and the LAN cable appears reliable.
You're asking about the PC's location and how it connects to networking equipment. It seems you want clarification on whether the cables are being routed directly to a router or switch, or if they pass through walls. You're also concerned about the possibility of using low-quality cables, noting that the speed settings are based on very basic hardware testing. The issue is likely due to a faulty cable, as it's common for such problems to stem from this. There are different types of Ethernet cables available, but many are not certified and can be easily counterfeit. Testing across various devices doesn't help much, since some perform better with non-compliant cables. It's difficult to properly assess cable quality at home or in small businesses due to cost constraints. The simplest solution is to replace the cable—even a basic 2.5G connection will work with Cat5e. For higher speeds like 10Gbps, Cat6a is recommended, but only if it's more affordable than Cat5e. Always ensure the cable is genuine copper wire with the correct size. Reputable sellers usually make this information clear.
I moved my PC to another location — I intended to test it on a different network, thinking a bad connection was causing the problem.
But it worked fine and achieved 11-13 Mbps download speed.
Apologies for the mistake; I was just writing about Cat 6.
View: https://www.youtube.com/watch?v=3MNWRYHH97M
It might be because of why it doesn't reach gigabit speeds. Unless your router is very old, it should support gigabit ports. Most modern motherboards come with 2.5Gb ports. In theory, an extremely old router could have 100Mbps ports. The main reason a port operates at 100Mbps instead of 1Gb is due to problems with the brown or blue wires (assuming standard color codes). It can support 100Mbps using just two pairs of wires. If it drops to 10Mbps, it indicates frequent errors while running at 100Mbps, prompting it to switch to a lower speed. This adjustment happens entirely in hardware. The only option is to manually set the speed to a slower rate. For optimal performance, keep it in auto mode. If your cable appears intact, consider adding a PCIe Ethernet expansion card, which are affordable. Alternatively, opt for a USB Ethernet port but ensure you have a free USB3 port; otherwise, speeds will cap around 400Mbps. The simplest first step is to use a high-quality cable.
I've never come across a NIC adjusting the link speed to 10Mbps after you've locked the speed in the settings elsewhere. It seems the connection should simply stop working. How do you know it's changed? Are you adjusting the speed through the device properties?
What gear are you employing? Router, switch, or specific models? Have you checked all ports on the device as well? Is your motherboard running the latest BIOS, and have you installed the most recent Realtek network controller drivers? Are the cables you're using long enough and connected directly to the router/switch?
When you tried the "good speed" at another location, what was the actual link speed of the interface? Were you testing against an Internet server, and did that site's service only offer 100Mbps, which could affect your results?
It’s entirely possible the port on your motherboard is faulty—perhaps due to poor soldering or a damaged connection when the cable was inserted. If your internet plan is under 1Gb, consider using a Gigabit PCIe card for testing. A 1Gb card costs around $15 on Amazon, while a "Brostrend" 2.5Gb card is only $18 and likely uses the same Realtek chip found in more expensive models. A USB3 Gigabit adapter would also work well and cost about $10. Order a quality Cat5e or Cat6 cable from brands like Monoprice, Cables to Go, Startech, or Cable Matters—any reputable name without inflated prices.
Could you please share the details of your USB network adapter and router model?