TP-link TX401 10GbE network card restricted to 4Gb speeds
TP-link TX401 10GbE network card restricted to 4Gb speeds
Hey guys! Im making a new thread for an issue ive been dealing with but continues to evolve. OG thread: TLDR, after troubleshooting the "bad" PCIE slot im now dealing with the damn card maxing out at 400MBs or 3.2gbit. i have reinstalled windows, drivers, etc. anything to get back to 10gbit. it doesnt matter which slot i use, even my top PCIE slot it seems like i can only achieve a third of the rated spec. im worried that my Truenas server (also using the same model of card) might be the issue. i do have a 10gig switch https://www.amazon.com/dp/B09LNLMH9Y?ref...title&th=1 but how do i trouble shoot that? apparently the return window closed on 5/2/2025 for the switch, or it might be the Motherboard. its already known for the bad PCIE slot. i went ahead and bought a new motherboard: https://www.amazon.com/dp/B0DGVBM73J?ref...title&th=1 but what if that solve the issue? everything was working at the 10gig spec when I posted the "solution" on 4/22/2025. but roughly on 5/2/2025 my network speeds went down to this so after a week of everything "working" it decides to "break"? i mean i did setup my own router using OPNsense few days after the fact. would that have anything to do with it? Ive tried power cycling my NAS but its all the same. maybe i should power cycle the router? Maybe the Switch crappe itself and now can only handle 4gig speeds? any help would be great. thank you
I found a way to configure a static IP address, but even with a direct link to my NAS I’m only getting 4Gbps speeds. So it seems secure. Now I suspect the motherboard itself might be the issue—it has the latest BIOS version, right?
I just received the green light from my supervisor to buy a new desktop, so I've been diving into this subject. Here are some insights you might find useful:
Possible causes for 10GbE speed throttling:
1. PCIe lane mismatch or slot constraints – Some budget motherboards have limited x4 slots, restricting full bandwidth.
2. Unmanaged switch restrictions – Devices like the QNAP QSW-1105-5T can't monitor traffic or handle errors properly, making performance unpredictable.
3. NIC driver or OS issues – Outdated drivers or tuning problems can cause hidden bottlenecks, especially with Windows under heavy use.
4. Cable or server-side problems – A failing NIC or mismatched MTU between devices can drop speeds unexpectedly.
Tips for building a reliable setup:
- Choose a motherboard with a full-bandwidth x4 PCIe slot and direct wiring to the chipset.
- Avoid sharing bandwidth with SSDs unless you know what you're doing.
- If possible, opt for a managed switch such as MikroTik or Netgear for better monitoring and control.
- After installation, test speeds using iperf3 and adjust MTU if needed (up to 9000 if supported).
You can also reach out to support via Windows subsystem or your OS for further help.
Thank you for your input! It’s unclear if the NIC on my NAS is experiencing the same problem. I only have access to testing via my desktop, which has been the main concern so far. All cables came with the CAT6a box. I’ve reinstalled Windows 11 and updated the NIC drivers multiple times. My motherboard is a X670 Aorus Elite AX rev1.0, which should support this NIC without issues. However, I feel like the early adoption of AM5 might have affected performance, possibly due to quality control. I’m aware the middle PCIe slot isn’t working either.
I hadn’t considered asking before, as it bypassed my thoughts, but maybe your problem lies with the cables themselves. Since you mentioned using shielded Cat6A cables (and possibly speed issues), I thought about testing and grounding—especially because shielded cables can underperform if not properly grounded or connected. --- Ways to Test Shielding (From Least to Most Expensive): --- 1. Visual Inspection (Free) Examine the RJ45 connectors at each end: Are they metal-plated or just plastic? Is the shielding or drain wire actually secured into the plug? If it’s plastic with no contact point for shielding, the cable is essentially unshielded. --- 2. Multimeter Continuity Test (Low-Cost if you already have one) Set your multimeter to continuity mode. Touch one probe to the metal shield of one connector, and the other to the far end. If it beeps or shows low resistance, continuity exists—but this only confirms end-to-end connection, not grounding. --- 3. Shield-Aware Cable Tester (Budget: ~$30–$60) Devices like the Klein Tools VDV526-200 or VDV501-825 can check: full pin continuity (1–8), shield continuity (S). These help verify proper wiring and termination, including the shield path. --- 4. Patch Panel & Ground Verification (Varies) If you’re using a wall plate or patch panel: Is it metal and grounded? Are the shielded cables connected to shield-compatible keystones? Does the whole system get earthed at least once (usually at the panel)? Without a solid grounding point, shielded cables might actually cause more interference. --- Final Thoughts: If continuity checks pass but performance doesn’t, the shielding may be: Not grounded, Terminated wrong, Or unnecessary in your setup. In environments where UTP Cat6A works better due to simpler routing and fewer grounding concerns, it could help. I’m not sure if you covered this before, but these are some points to think about? Let me know.
I also had an extra CAT6a cable, but changing or rearranging all three still capped my speeds at 4Gbps. No real gain. I’m getting frustrated—maybe the issue is with the NIC in my NAS. It’s not a total disaster, but it’s really annoying to troubleshoot.
Checked out a discussion on the TP-links forum about comparable problems. Someone swapped their CAT6a cables, so I headed to Amazon for alternatives!
Amazon is being playful—only one cable arrived! I bought two and got one cable plus a box full of repellent waste. https://a.co/d/75J9wHZ I installed the new motherboard, the 10G NIC was shipped, and I reinstalled Windows Home just to be safe. I’m wondering if Microsoft restricts certain support, like 10G networking, in Windows 11 Pro? Am I missing something and should upgrade my OS?
I’m really confused about what to do next. I tried swapping the motherboard but nothing changed anything. I moved the 10Gb cards between machines without any success. I’ve also added NICs and a switch to both systems, yet nothing works. It’s frustrating—I feel like I’m just wasting time and money. I really want a career in IT support or networking engineering, but I can’t even get the basic hardware set up. I’m starting to feel defeated.