This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(12.8, 53%, 11%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ER%3C/text%3E%3C/svg%3E)
I can only get them to run at 2 Gbits/sec per iperf3 in Windows 11 Pro 23H2 64-bit using a 50 foot Cat 8 patch cable to connect the computers directly (ASUS Prime Z370-P motherboard; Intel Core i7-8700K processor). They are Intel X550-T2 and Asus XG-C100C, running latest drivers and firmware. Under Settings>Network & internet>Ethernet> shows Link speed (Receive/Transmit): 10/10 (Gbps), but under Settings>Network & internet>Advanced network settings> shows Link speed: 1410 (Mbps) [same result with Windows in Safe Mode with networking]. I have tried all of the suggestions I could find online, and those from the NIC manufacturers (Speed & Duplex=Auto Negotiation; turn off Interrupt Moderation; disable all setting with "Offload" in the name; disable Flow Control; set autotuninglevel=normal; and turn off networking built into motherboard). No improvement. Any suggestions would be appreciated.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(275.2, 68%, 36%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ESA%3C/text%3E%3C/svg%3E)
Hello,
I have the same issue.
I tried to set jumbo packets to 9014 and sorted out the problem but internet stopped to work (Chrome wasn't able to open webpages) so had to revert back to "disabled".
Then I made a clean installation of Windows 11 23H2 and used NIC drivers from Marvell version 3.1.8. and transfer speed between two PCs was as should be, about 1,1 GB/s, but then after the installation of windows updates and drivers, the speed went down to 200/400 MB/s.
Tried to apply all the suggestions I found, such as recv segment coascelensce disabled, or transfer/receive buffer value modification but nothing worked.
Thanks for any suggestion you may give to fix this problem.
Set Jumbo Packet to 9014 Set Receive Buffer to 4096 Set Transmit Buffer to 16384
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(316.8, 70%, 40%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMH%3C/text%3E%3C/svg%3E)
This fixed the issue for me, having a TP-Link TX401 10G. I had to set the Transmit Buffer to the max allowed value of 8186, and the Jumbo Packets to the max value too, 16348. That made the CPU go to 100% and download from steam at 3.2 Gbps of the 4 I pay (speedtest.net shows 4gbps without issues)
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(313.6, 55.00000000000001%, 40%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EHL%3C/text%3E%3C/svg%3E)
Hello, Thank you for posting in Q&A forum. I believe you have done some basic troubleshooting for this issue, here I will also list some methods that we can try and give some proposals from Windows aspects, please check below: Check the hardware 1.Switch Cable and see if it works 2.Check the network interface is plugged in the correct PCIe slots on motherboard. From Windows aspect:
Thank you very much for your suggestions! In answer to your suggestions: 1. I have tested with several different Cat 7 and Cat 8 cables. 2. I have tested using each available PCIe 3 slot. In answer to Windows suggestions: 1. Firmware for motherboard and NIC are most current, as is the NIC driver. 2. These have been verified. 3. Unchecked "Allow the computer to turn off this device to save power" on the Power Management tab on the NIC properties page. 4. CPU went from 2% utilization to 9% utilization. Memory did not change. 5. TCP Window Auto-Tuning Level is set to normal. Running iperf3 still produces about 2 Gbits/sec. However..... As a further test I ran Linux from a flash drive on two of the computers. Running iperf3 produced 6.5/7.4 Gbits/sec running between the two computers (it didn't matter which was running as the server). The Windows computer running as the client could connect to either Linux computer at similar speeds. However, if the Windows computer was running as the server, the Linux computers, running as client, could only produce about 2.2 Gbits/sec. From this I conclude that there is no problem with the hardware (motherboard, NIC, cabling, etc.) since Linux can achieve reasonable speeds. The problem would seem to be either Windows 11, or the Intel driver for Windows 11. Any help you could provide along those lines would be greatly appreciated! Thanks, Michael