blitcp vs FastCopy
First, the disambiguation: FastCopy is a well-established Windows copy tool by Shirouzu Hiroaki, around since 2004 — blitcp (this project) is an unrelated, Apache-2.0 licensed CLI for Linux, macOS and Windows. blitcp was previously named fast-copy, which was confusingly close to FastCopy's — that's exactly why it was renamed. Both tools want the same thing, copies that are faster than what the OS ships with, but they get there very differently.
The measured difference
Same workload, same machine: 9,578 files / 890.8 MB, USB 2.0 external HDD to internal SSD (NTFS), Windows 11, full reboot before each run, Windows Defender active for both tools:
| Tool | Time | Verification |
|---|---|---|
| blitcp | 2 m 28 s | ON — every file hash-checked |
| FastCopy 5.11 | 3 m 38 s | off |
blitcp did the verification pass and still finished more than a minute ahead. Full methodology here.
Feature differences that matter
| blitcp | FastCopy | |
|---|---|---|
| Platforms | Linux, macOS, Windows | Windows (macOS port exists) |
| License | Apache-2.0, fully free | GPL-ish source, donation-ware |
| Read strategy | physical-offset sorted + small-file bundling | large parallel buffers |
| Post-copy verification | on by default | optional |
| Content dedup → hard links | yes, cached across runs | no |
| SSH / S3 / Azure / GCS targets | built in | no (local & SMB paths) |
| Sparse files / VM images | SEEK_DATA-aware, holes preserved | no special handling |
| Shell integration | no | yes |
When FastCopy is still the better tool
Honest answer: it's a 20-year-old, battle-hardened Windows native with Explorer integration and fine-grained include/exclude filters that many admins know by heart. If your world is Windows-to-Windows local and SMB copies and you rely on its filter syntax, it remains a fine tool. blitcp earns its place when you want the same job to also run on Linux servers and NAS boxes, push over SSH or to object storage, deduplicate, and hand you a hash-verified result by default.
Download blitcp · Windows install & SmartScreen notes: /install/windows/
Also compared: blitcp vs rsync · blitcp vs cp · blitcp vs scp / SFTP · blitcp vs Robocopy · blitcp vs TeraCopy · full benchmark methodology