Why is transferring hundreds of thousands of files over Wi‑Fi so slow?

The most reliable solution is to remove the old laptop’s drive and connect it to the new one with a SATA-to-USB adapter or another external drive enclosure. That avoids Wi‑Fi overhead and is usually much faster and more stable. An external drive would also be useful for future transfers and backups.

Hundreds of thousands of tiny files can be extremely slow to transfer, especially if the source laptop uses a mechanical hard drive. Each file requires separate filesystem and network overhead, so the transfer rate can collapse even when the Wi‑Fi connection itself is fine. If possible, compress the folders into one or a few archive files first, then transfer those archives and extract them on the new laptop.

If you later get Ethernet adapters or cables, a wired connection should be much faster and more consistent than Wi‑Fi. Don’t assign both laptops the same IP address, though—that causes an address conflict. Let them obtain addresses automatically, or configure two different addresses on the same network.

A local transfer tool such as LocalSend may perform better than ordinary network file sharing and is easy to use on devices connected to the same network. Still, it won’t completely eliminate the slowdown caused by hundreds of thousands of small files, so archiving them first is likely to help the most.