The Realtek 2.5Gbe network card has a maximum speed of 200Mbps.
The Realtek 2.5Gbe network card has a maximum speed of 200Mbps.
I’m experiencing a severe loss of motivation. I added a new network card to my main PC to take advantage of the 2.5GbE fibre connection I’ve set up. The card is linked to a 2.5GbE switch using a CAT6E cable (2 metres) which connects via fibre to the router. There’s another PC connected to the same router, which offers an internet speed of 510Mbps thanks to my 500Mbps fibre broadband. However, the first machine only manages around 210Mbps unless I’m fortunate. The card settings are configured with Speed & Duplex set to Auto Negotiation and EEE Max Support Speed at 2.5Gbps Full Duplex. I’ve also installed the newest drivers for Windows 11. Assistance needed!
It may depend on the network hardware (switch / router) you have. Some routers have issues when you have such a large mis-match between LAN speed (2.5GE) and WAN speed (500Mbit). One thing you could check is to see if you can enable flow control on the router. That may allow things to work more efficiently.
I considered it, but the second PC, an A Dell Optiplex, works fine. The port where my Asus is connected displays 2.5Gbps. The switch is unmanaged with two SFPs that auto-negotiate from 1Gbps to 10Gbps. The Ethernet ports support speeds from 10Mbps up to 2.5Gbps, so issues shouldn't occur. I also attempted a managed gigabit Ethernet switch and encountered the same problem.
I would check if there is flow control available on the Asus router. It might be causing buffering problems.
It could also be a Windows issue. I would try installing a portable Linux on a thumb drive and boot it to test. This would help rule out Windows as the cause.
Did your motherboard come with any "game enhancer" software? Something like Asus game first software? That software can artificially slow down speedtest.
I believe the router and switch can be reduced in cost since Optiplex isn't facing this problem. I also used a Draytek 2866 and achieved the same outcome on both devices. I need to resolve this because reaching Gigabit broadband would be useless if my development server (the Asus) can't even approach 500Mbps. The ability to download software and patches quickly is essential, as some files exceed 1 gigabyte in size. Since it's a development machine, there are no games or related software—except for MS Solitaire while downloading/uploading.
The software in question might not even be installed on your system. Several motherboards and graphics cards, particularly those from Asus, will automatically install a gaming accelerator along with the unnecessary bloatware that comes with the drivers unless you disable the installation options. This is just one of the frequent causes of such problems that you might not be aware of.
How are you measuring the speed? Does it only appear in speedtest, or do you also notice issues when downloading files? Have you tested different browsers?
The aim now is to determine whether the problem stems from hardware, a Windows setting, or a driver issue. As suggested by kanewolf, you could attempt using a bootable Linux image on a USB drive. These usually come with a browser pre-installed, allowing you to run speed tests consistently.
You might also try running an outdated line mode tool such as IPERF on both devices. This tool is very basic and unaffected by browser changes. It mainly evaluates the driver and hardware performance without relying heavily on the CPU or GPU. If both machines have 2.5Gb ports or faster, you should be able to observe close to 2.5Gb transfer speeds using this method.
Would the results change if you connected it to a 1Gb port? 2.5Gb remains quite unstable for some reason.
I'm facing the same problem with this network adapter: an MSI X670E Tomahawk. Wi-Fi reaches 700 Mbps, yet Ethernet drops to 250 or 350 Mbps occasionally. Speedtest reports 600 Mbps, but Fast.com remains stuck between 250 and 350. Switching auto negotiation to 1 Gbps doesn't help.
Similar to the problematic ASUS WTFast Game Accelerator that Bill discussed, MSI Dragon Center features a less obvious accelerator named Lan Manager. Its uninstaller can be found in the directory C:\Program Files (x86)\MSI\One Dragon Center\LanManager.
The problematic MSI Lan Manager feature is cFosSpeed Traffic shaping, which may also be available as a separate install named "Gigabyte Speed"