File copy from RN528 to RN424 - which method is fastest?

I recommend using Third-Party File Copy Tools and as you mentioned (Fastcopy) ,also there are file copy tools like Gs Richcopy 360, Goodsync, or Teracopy that offer enhanced features and faster transfer speeds compared to the default Windows file copy. These tools often provide better control over the transfer process, including options for multi-threading, error handling, and network optimizations. You can try using one of these tools to see if it improves the transfer speed.

Another popular option  (RSYNC) :

• Optimized for Network Transfers: As a command-line tool specifically designed for efficient network file synchronization, it can be significantly faster than Windows Explorer for large transfers.
• Benefits:
  • Transfers only changed file portions, reducing network traffic.
  • Handles interrupted transfers gracefully.
  • Offers a high degree of control over the process.

Remember that even with these methods, the 1GbE link will ultimately limit your transfer rate. If you frequently deal with large data transfers and require faster speeds, consider upgrading to 10GbE networking for future-proofing.