Yesterday, 11:55 AM
You’re absolutely right to expect more from the write performance on the Windows side, especially over 10GbE. Based on what you’ve described, it sounds like the hardware is up to the task, so the bottleneck is most likely software or driver-related.
Here are a few things worth checking or trying:
1. NIC Driver and Firmware
Double-check that the 10GbE adapter in the Windows machine is running the latest driver and firmware from the manufacturer’s site (not just what Windows Update installed).
2. Jumbo Frame Consistency
Ensure all devices, including switches, are consistently set to the same MTU (typically 9000). In some setups, Windows can silently revert to 1500 if the network path isn’t clean.
3. SMB Multichannel
If your adapter supports multiple queues and RSS is active (which you’ve already enabled), ensure that SMB Multichannel is not disabled via group policy or registry. It can help boost throughput significantly on Windows.
4. Storage Write Target
What drive is the data being written to on the NAS? SSD or HDD RAID? If it’s a slower array, Windows may behave more conservatively with buffering and write caching. Also try disabling Windows Defender real-time protection temporarily to see if there’s an impact.
5. Disable Large Send Offload (LSO)
In Device Manager > Network Adapter > Advanced tab, try disabling “Large Send Offload (IPv4 and IPv6)” and test again. Sometimes this offload causes latency with high-throughput transfers.
6. Test with iperf3 on Windows
Use iperf3 with the NAS or Mac as server, and the PC as client to get raw network performance values independent of SMB/file system overhead. That will help narrow down if the issue is truly network-related or something on the file stack.
7. File Copy Method
Try testing with tools like FastCopy or TeraCopy, as the default Windows Explorer copy is not always representative of actual performance, especially with lots of small files.
Here are a few things worth checking or trying:
1. NIC Driver and Firmware
Double-check that the 10GbE adapter in the Windows machine is running the latest driver and firmware from the manufacturer’s site (not just what Windows Update installed).
2. Jumbo Frame Consistency
Ensure all devices, including switches, are consistently set to the same MTU (typically 9000). In some setups, Windows can silently revert to 1500 if the network path isn’t clean.
3. SMB Multichannel
If your adapter supports multiple queues and RSS is active (which you’ve already enabled), ensure that SMB Multichannel is not disabled via group policy or registry. It can help boost throughput significantly on Windows.
4. Storage Write Target
What drive is the data being written to on the NAS? SSD or HDD RAID? If it’s a slower array, Windows may behave more conservatively with buffering and write caching. Also try disabling Windows Defender real-time protection temporarily to see if there’s an impact.
5. Disable Large Send Offload (LSO)
In Device Manager > Network Adapter > Advanced tab, try disabling “Large Send Offload (IPv4 and IPv6)” and test again. Sometimes this offload causes latency with high-throughput transfers.
6. Test with iperf3 on Windows
Use iperf3 with the NAS or Mac as server, and the PC as client to get raw network performance values independent of SMB/file system overhead. That will help narrow down if the issue is truly network-related or something on the file stack.
7. File Copy Method
Try testing with tools like FastCopy or TeraCopy, as the default Windows Explorer copy is not always representative of actual performance, especially with lots of small files.