DiskfernMeasured performance
Real measurements. Clear results.
Measured on an M4 MacBook Air with 16 GB memory, using the same kind of build you download. 2,888 measurements across 330 tests.
- Full startup disk
- ~16 s
- About 2.9 million files scanned
- Selective Finder search
- 2.35 ms
- videos > 1gb · 2 million records
- Search index
- 184 ms
- Built for 2 million records
- Saved scan restore
- 18.6 ms
- 500,000 items back from disk
MacBook Air · Apple M4 · 16 GB · macOS 26.6
A whole startup disk in about 16 seconds
A full scan of the Mac’s own startup disk, the largest and busiest place Diskfern looks.
- Files scanned
- ~2.886M
- Folders
- ~472.6K
- First full scan
- 16.055 s
- Scan again
- 15.949 s
- Protected folders skipped
- 401
Time for the scan engine to traverse readable folders on the startup disk, using Diskfern’s normal settings. Drawing the map and saving the scan come after and are not included. Folders macOS keeps private are skipped and counted.
Scan speed that holds up at scale
The same scan on test folders of growing size, measured ten times each.
| Items | Median | p95 |
|---|---|---|
| 10,000 | 9.12 ms | 9.72 ms |
| 100,000 | 83.04 ms | 84.38 ms |
| 500,000 | 3.274 s | 3.357 s |
Diskfern reads file details, not file contents, so these folders hold many small generated files.
Results begin arriving quickly
- Median
- 256.24 ms
- p95
- 256.31 ms
How soon the first results reach the app during a 500,000-item scan. The map is drawn from them next; drawing time is not included.
Finder search across 2 million records
Plain-language queries, typed the way people ask. Times in milliseconds.
| Query | Median (ms) | p95 (ms) |
|---|---|---|
| videos > 1gb | 2.35 | 2.75 |
| last week videos | 2.21 | 2.47 |
| my videos from 2 sept | 2.22 | 2.56 |
| birthday videos from 2 sept >500mb | 2.54 | 2.59 |
| pdf this month | 5.88 | 6.29 |
| documents except pdf | 5.70 | 6.15 |
| largest videos | 6.58 | 7.01 |
| newest videos | 7.05 | 9.49 |
| a name with no match | 2.97 | 2.98 |
| report (broad match) | 862.63 | 890.68 |
Built for large indexes
- Build the search index
- 184.4 ms
- 2 million records · p95 191.1 ms
- Understand a typed query
- 0.01–0.04 ms
- Plain-language parsing, before the search runs
Treemap and sunburst layouts
Time to work out where every tile and ring goes. Times in milliseconds.
| Tiles or rings | Treemap | Sunburst |
|---|---|---|
| 500 | 0.122 | 0.058 |
| 1,000 | 0.243 | 0.072 |
| 3,000 | 0.738 | 0.238 |
| 5,000 | 1.254 | 0.409 |
Layout calculation only. Rendered frame rate is measured separately and is not claimed here.
Everyday features
Typical times for the work behind each view, on test scans.
List view
- 10,000 items
- 0.107 ms
- 100,000 items
- 0.490 ms
- 500,000 items
- 0.659 ms
Preparing the sorted list from a finished scan.
Smart Highlights
- 10,000 items
- 10.6 ms
- 100,000 items
- 115 ms
- 500,000 items
- 610 ms
Time to classify a whole scan. A speed figure, not an accuracy claim.
Filters at 500,000 items
- Large files
- 0.048 ms
- Size range
- 0.051 ms
- Not opened lately
- 5.21 ms
Saved scans at 500,000 items
- Save
- 60.37 ms
- Restore
- 18.62 ms
Collector
- 1 item
- 0.03 ms
- 10 items
- 0.28 ms
- 100 items
- 2.98 ms
- 1,000 items
- 68.6 ms
Adding and checking items before review. Moving to Trash is not included.
Inspector
- Details for one item
- 0.058 ms
p95 0.064 ms.
Stopping a scan
How long a 100,000-item scan takes to stop after you cancel. Times in milliseconds.
| Cancelled | Median (ms) | p95 (ms) |
|---|---|---|
| Immediately | 0.030 | 0.108 |
| After 1 ms | 0.347 | 2.746 |
| After 10 ms | 0.393 | 1.125 |
Sizes you can trust
Mac file systems have edge cases that make sizes easy to get wrong. Each one below has its own test.
Hard links
A file with two names is counted once.
Sparse files
Sized by the space they really use, not their apparent length.
APFS clones
Checked against real clones made on the APFS test disk.
Unicode names
Accented, Chinese and emoji names are read, and found by search in either Unicode form.
Broken symlinks
Recognised and refused as cleanup targets.
Symlink loops
Detected and refused as cleanup targets.
Symlink escapes
A link pointing outside the chosen folder is refused as a cleanup target.
How we measured
Method
- MacBook Air with an Apple M4 chip and 16 GB memory
- macOS 26.6 on the internal APFS startup disk
- The same kind of build you download, not a debug build
- Warmup runs first, then 10 measured runs for most tests
- No slow runs thrown away. Median is the typical run; p95 means 95% of runs were at least that fast
- 2,888 measurements across 330 tests
Limits
- Results vary with hardware, storage speed, file count, permissions and system load. They are not a guarantee or a comparison with other apps.
- Files had been read recently, which can make a scan quicker than on a Mac that has just restarted.
- Scale tests use generated test folders. Diskfern reads file details, not file contents, so the files themselves are small.
- Layout figures are calculation only. Rendered frame rate is measured separately and is not claimed here.
- The startup-disk figures come from one full scan and one repeat scan.
- Search timings vary by query. The selective videos > 1gb query took a 2.35 ms median; the broad report query took 862.63 ms across the same 2 million records.
Get your space back. Start with a free scan.
Explore the files and folders Diskfern can read. Your files stay on your Mac, and nothing is removed until you say so.
macOS 14 Sonoma or later · Apple silicon and Intel