Unlocking the Power of SMB Compression in Windows Server 2025
In the ever-evolving landscape of IT infrastructure, efficient data transfer is paramount. Windows Server 2025 introduces a game-changing feature: SMB Compression. This innovation is designed to streamline data transfers, reduce network congestion, and enhance overall system performance.
What is SMB Compression?
SMB (Server Message Block) Compression allows files to be compressed as they are transferred over the network. This eliminates the need to manually compress files before transfer and decompress them afterward. The result? Faster and more efficient data transfers, especially beneficial for networks with limited bandwidth.
Key Features of SMB Compression
- Multiple Compression Algorithms: Windows Server 2025 supports several compression algorithms, including XPRESS (LZ77), XPRESS Huffman (LZ77+Huffman), LZNT1, and the newly supported LZ4. This flexibility ensures optimal performance across different scenarios.
- Enhanced Network Efficiency: By compressing files during transfer, SMB Compression reduces the amount of data sent over the network. This is particularly useful for congested or slower networks, such as 1 Gbps Ethernet or Wi-Fi.
- Compatibility and Security: SMB Compression supports SMB signing and encryption, ensuring that compressed data remains secure during transfer. It also works seamlessly with SMB over QUIC and SMB Multichannel.
So how to configure this, I have 2 vm’s both server 2025 and I’m not using WAC for this time.

Create a folder on the file server and create the share with powershell as there is no option to set this in the GUI as the trick is in the CompressData $true
New-SmbShare -Name “MVPData” -Path “C:\mvpdata” -CompressData $true

Now On the Domain joined Client we need to create a net use to make sure the compression is used.
SMB Compression is particularly effective in environments with large volumes of data and limited network bandwidth. For instance, organizations with extensive file shares or remote offices can benefit significantly from reduced transfer times and lower network congestion.
now On the client use powershell or net use to add the share
New-SmbMapping -LocalPath “q:” -RemotePath “\WIN-BQB4LBSM99E.mvp.local\mvpdata” -CompressNetworkTraffic $true
NET USE * \WIN-BQB4LBSM99E.mvp.local\mvpdata /REQUESTCOMPRESSION:YES
In this case I copy the Windows 2025 installation folder over 3 times 16,7GB as copy this only one time will not give me enough time to create a snaphot.

So first a normal copy to the C$

now 4 times more data.

As you can see less bandwidth bit more CPU but massive speed. just on copy files As it was not one big file.

If you are using Windows server 2025 as a file server and your clients are up to date you could bennefit from this.
While SMB Compression in Windows Server 2025 offers many benefits, there are some potential downsides to consider:
- Increased CPU Usage: Compressing and decompressing data requires additional processing power. This can lead to higher CPU usage on both the server and client machines, potentially affecting performance, especially if the hardware is not robust.
- Latency: The process of compressing and decompressing data can introduce latency. This added delay might impact applications or scripts that rely on quick data access.
- Compatibility Issues: Not all third-party tools and applications support SMB Compression. This can limit its use in environments that rely on specific software for data transfer.
- Network Conditions: While SMB Compression is beneficial for slower or congested networks, it might not provide significant advantages on high-speed networks. In some cases, the overhead of compression and decompression might outweigh the benefits.
- Complexity in Configuration: Setting up and managing SMB Compression might require additional configuration and monitoring, which can add complexity to the IT infrastructure.
Despite these potential downsides, SMB Compression can still be a valuable feature, especially in environments where network bandwidth is a limiting factor. It’s important to evaluate your specific use case and test the feature to determine its impact on your system.
See what is new in Server 2025
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