{
  "id": 3902581,
  "title": "Debugging my new network, when 10 Gigabit Ethernet Runs at 300 Megabits",
  "url": "https://urgent.news/2026/08/28/debugging-my-new-network-when-10-gigabit-ethernet-runs-at-300-megabits",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-08-28T05:52:13.000Z",
  "source": {
    "name": "Lobsters",
    "slug": "lobsters",
    "url": "https://www.hanselman.com/blog/debugging-my-new-network-when-10-gigabit-ethernet-runs-at-300-megabits"
  },
  "original_language": "en",
  "account": "In his latest home lab upgrade, the author encountered an issue where his new 10 Gigabit Ethernet network was only achieving speeds of 300 Megabits per second. Despite all components, including the Intel E610-XT2 10GbE card, NAS, and miniPC, reporting 10 Gigabit speeds, the actual file transfer rates were significantly lower. The author initially suspected the NAS and its spinning disks, but after testing, realized the problem was not with the storage hardware. He then proceeded to test the network directly between the Windows desktop and the miniPC using iperf3, discovering that the issue was actually a Windows/NIC problem. Upon investigation, he found that the Ethernet driver's receive buffers were set to the default value of 512, which was inadequate for 10 Gigabit speeds. Increasing the buffer size resolved the issue, as the packet discard count dropped from nearly a million to zero, and the receive throughput improved from 1.33 Gbit/sec to 5.15 Gbit/sec. However, the transmit direction was still sluggish at 313 Mbit/sec, prompting the author to disable Large Send Offload (LSO) V2 for IPv4. This change resulted in a significant boost, increasing the transfer speed from 313 Mbit/sec to 7.03 Gbit/sec. While LSO is generally beneficial, in this particular case, disabling it provided a substantial performance improvement. The author emphasizes the importance of ruling out other factors before modifying network settings, concluding that the lesson learned is not to disable LSO across the board, but rather to carefully measure and adjust network configurations based on specific circumstances.",
  "summary": null,
  "key_points": [
    "10 Gigabit Ethernet network only achieving 300 Mbps speeds",
    "Windows/NIC problem causing low file transfer rates",
    "Disabling LSO V2 for IPv4 boosts transmit speed to 7.03 Gbit/sec"
  ],
  "editors_take": "Tweaking specific network settings, like receive buffers and Large Send Offload, can greatly improve 10 Gigabit Ethernet performance, but requires careful testing to avoid broadly applied but ill-suited fixes.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}