MacOS Finder Copies Faster Sequentially

MacOS Finder Copies Faster Sequentially | Generated by AI

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Question: In macOS, is parallel copying slow or fast? For example, with 30 GB across 3 folders, is it faster to put them into one big folder and copy once, or to copy the 3 folders simultaneously (in parallel)?

Answer:

In typical real-world cases on macOS (using Finder), copying the 3 folders separately but simultaneously (parallel) is usually a bit slower than putting them into one parent folder and copying that single folder once (sequential inside one operation).

Here is why and when it matters:

Putting everything in one parent folder and copying once is generally faster (or at least more consistent) for these reasons:
- Finder performs one overall preparation phase (scanning metadata, building the file list).
- It usually processes the copy more linearly / sequentially at the I/O level → better sustained throughput, especially on spinning hard drives, network shares, USB drives, or when there are many files.
- Less contention / context switching inside Finder.
- macOS Finder (and also APFS) tends to dislike many parallel heavy write streams to the same destination volume.
Starting 3 separate copy operations at the same time (parallel) is usually slower overall because:
- Finder creates multiple copy queues / worker threads.
- This leads to more seeking, more metadata operations happening concurrently, and more competition for disk bandwidth → especially noticeable on HDDs, USB flash drives, network shares, or even SSDs when many small files are involved.
- Real-world user reports and benchmarks (even recent ones from 2024–2025) consistently show that parallel Finder copies to the same destination volume often give worse total throughput than one big sequential job.

Practical recommendation for your 30 GB / 3 folders case:

Best (fastest & most reliable) → Put the 3 folders inside one parent folder (e.g. “Temp_30GB”) and copy that single parent folder once.
Still acceptable but usually a little slower → Select all 3 folders and copy them at the same time (parallel).
Worst → Copy one folder → wait until finished → copy next → wait → copy last one (unless the folders have dramatically different file count or size patterns).

Extra notes:

If the folders contain mostly large files (videos, disk images, archives etc.) → the difference is usually small.
If the folders contain many small files → putting them into one parent folder becomes clearly faster (sometimes dramatically faster).
On very fast NVMe SSD → SSD → SSD local copies the difference is often small (both ways are fast).
On USB 3.0/3.1 flash drive, external HDD, or network copy → single-folder copy is noticeably more reliable and usually faster.
If you want maximum speed and don’t mind the command line → use cp -R or rsync -a for one parent folder — often faster than Finder anyway.

Summary rule of thumb (macOS Finder):
One big copy operation > parallel copy of several folders > sequential one-by-one copy.

References:

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