guidox / PC
Check **Get-SmbClientConfiguration** and **Get-SmbMultichannelConnection**, then compare a large sequential copy against the link speed. Signing and multichannel are the first two levers.
A copy of one large file isolates throughput from per-file overhead. The result in MB/s is the number every change has to improve.
$src = 'C:\temp\test.bin'
fsutil file createnew $src 2147483648
Measure-Command { Copy-Item $src '\\PC02\share\test.bin' -Force } | Select-Object TotalSeconds
Get-NetAdapter -Name 'Ethernet' | Select-Object LinkSpeed**RequireSecuritySignature** costs measurable throughput on older CPUs. **EnableLargeMtu** and **SMB2** support decide how much data moves per round trip.
Get-SmbClientConfiguration | Select-Object EnableSecuritySignature,RequireSecuritySignature,EnableLargeMtu,MaxCredits,UseMultiChannel,SMB2Dialect
Get-SmbConnection | Select-Object ServerName,ShareName,Dialect,NumOpens
Get-SmbClientNetworkInterface | Select-Object InterfaceIndex,IpAddress,RssCapable,LinkSpeedTwo adapters or a 2.5 Gb link only help when multichannel is active. A single connection with one channel is a single stream, no matter the hardware.
Get-SmbMultichannelConnection | Select-Object ServerName,ClientIPAddress,ServerIPAddress,ClientLinkSpeed,ServerLinkSpeed
Get-SmbClientConfiguration | Select-Object UseMultiChannel
Get-NetAdapter | Select-Object Name,LinkSpeed,StatusSigning is the biggest lever on a trusted LAN, and it needs both ends. Multichannel needs at least two interfaces or RSS support on both sides.
Set-SmbClientConfiguration -RequireSecuritySignature $false -Confirm:$false
Set-SmbClientConfiguration -EnableMultiChannel $true -Confirm:$false
Get-SmbClientConfiguration | Select-Object RequireSecuritySignature,EnableMultiChannel
# repeat the copy test and compare with the baselineA client change fails when the server requires signing. The server's own configuration and its disk performance decide the ceiling.
Get-SmbServerConfiguration | Select-Object RequireSecuritySignature,EnableSMB2Protocol,MaxWorkItems,MaxThreadsPerQueue
Get-SmbShare | Select-Object Name,Path,CachingMode
Get-Counter '\PhysicalDisk(*)\% Disk Time' -SampleInterval 1 -MaxSamples 3 | Select-Object -ExpandProperty CounterSamples | Select-Object InstanceName,CookedValueRepeat the exact same copy. A gigabit link tops out near 110 MB/s, and a 2.5 Gb link near 280 MB/s; anything close to that is the hardware, not the protocol.
Measure-Command { Copy-Item 'C:\temp\test.bin' '\\PC02\share\test2.bin' -Force } | Select-Object TotalSeconds
Get-SmbConnection | Select-Object Dialect,NumOpens
Get-Counter '\SMB Client Shares(*)\Bytes Total/sec' -SampleInterval 1 -MaxSamples 3 | Select-Object -ExpandProperty CounterSamples | Select-Object InstanceName,CookedValueThe link negotiated at 100 Mbps. Check LinkSpeed on both ends and the cable before tuning SMB.
Per-file overhead. Use robocopy with /MT to run several streams in parallel instead of changing SMB settings.
A domain policy sets it on the server. Client-side changes are ignored until the policy changes.
Both ends need two interfaces on the same subnet, or RSS support. A single cable cannot produce two channels.
It removes protection against tampering on the wire. Only do it on a trusted, switched LAN, never across the internet.
For compressible data over a slow link yes. On a gigabit LAN the CPU cost usually outweighs the gain.
Only when every device in the path supports the same MTU. A mismatch causes retransmissions and a slower copy.
Set RequireSecuritySignature back to $true and EnableMultiChannel to $false if it was off, using Set-SmbClientConfiguration, then delete the test files.
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