I have the following setup (excuse "ASCII Art"):

laptop SSD (attached via SATA) <-> 1Gbps wired ethernet <-> server HDD (attached via USB3.0)

Where laptop and server both run Windows Server 2012 R2, and the server drive is mounted on the laptop via standard Windows "Advanced File Sharing" (i.e., standard Windows 8 era SMB).

Now, I do file transfers via the command line (robocopy).

Server to laptop: Continuous 330Mbps achieved.

Laptop to server: Continuous 940Mbps achieved.

Why the ~3x speed difference based on direction?

  • That's common in all hardware, there is always a read and a write speed. Read hardware profile specs. – ejbytes Mar 12 '17 at 8:31
  • Try getting storage read/write asymmetries out of the picture by running iperf, which doesn't use the disk. If iperf gives symmetric numbers, then the asymmetry probably lies with the mass storage devices or maybe with some tuning issue in the file sharing protocol. – Spiff Mar 12 '17 at 17:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.