Windows 10: Question about SMB multichannel on Windows 11 Pro 23H2

Hi everyone,I recently did some tests about the SMB multichannel, and the results made me confusing, and I hope someone can tell me what went wrong.Hardware:A Synology NAS with 8*14TB HDDs, RAID5, four built-in 1Gbps LAN ports. The transfer speed of the disks array could reach 500MB/s read or write via local USB 3.0 to array, so disk speed would not be the limitation.A Ryzen 5950X based PC with two 2.5Gbps LAN ports, a PCI-E 4.0 NVMe SSD as local disk Windows 11 was installed on another NVMe SSD, so the disk w/r speed would not be the bottleneck.An ASUS RT-AX89X router, which was capable of

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Event ID: 30822 Failed to establish an SMB multichannel network connection.

Something here is probably what you're looking for however: SMB multichannel troubleshooting - Windows Server

 

Cannot get SMB Multichannel to work (Win 8.1 <-> 10)

Thank you for the advice, I created a new thread there:

Cannot get SMB Multichannel to work (Win 8.1 <-> 10)

 

Windows 11 PRO 22H2 Slow SMB Download

I use Windows 11 PRO 22H2 to transfer files to my NAS server.

The transfer speed of big files (3GB+) from Windows to NAS is on expected level. The transfer speed is about 260+ MB/s on 2.5 Gbps connection, if connection is 2x2.5 Gbps (multichannel SMB is ON) the transfer speed is about 550+ MB/s. It works more or less OK.

BUT, the transfer speed of big files (3GB+) from NAS to Windows is very low. The transfer speed is about 140 MB/s (stable) on 2.5 Gbps connection and 280-290 MB/s (stable) on multichannel SMB connection (2x2.5 Gbps). So, reading files from NAS is 2 times slower than writing the same big file(s) to NAS. I use different Windows Clients to transfer files e.g. Windows File Explorer or Windows Commander. The results are more or less the same, the reading operation is about 2x slower than writing operation.

Windows Task Manager does not report CPU, memory, network or destination disk overload, a lot of free resources.

I have no idea what is cause of this issue. Any idea what is the reason of the problem ?