DuoBolt vs Gemini 2 — Speed & Feature Comparison

Gemini 2 (MacPaw) is one of the most polished consumer duplicate finders for macOS. It’s well-designed and easy to use, but its scan engine is built for Photos.app-style libraries rather than for source trees or network volumes. In our benchmark suite it finished last of five tools on all three kinds of storage, and the gap is widest over a network: DuoBolt is 21.9× faster on a NAS share, and 11.66× across a source tree of 1.69 million files.

Benchmark Results

All tests ran on an Apple M2 Max, macOS 27.0, on 20 September 2026, with each tool’s own cache cleared before every run, a 1 KB minimum file size and exact duplicates only. Lower times are better.

Gemini 2 was run in duplicates-only mode, with similarity detection off, so the comparison measures byte-identical duplicate detection — the workload both tools are designed to do. Its minimum file size was set explicitly to 1 KB rather than left on Automatic, which picks an undisclosed threshold from the size of the job and so cannot be reproduced or compared against another tool.

Storage	DuoBolt	Gemini 2	DuoBolt advantage
Internal SSD — 394 GiB, 1.69M files	38s	7m23s	11.66× faster
USB-C SSD — 797 GB	5m17s	11m20s	2.15× faster
NAS over SMB — 1.09 TiB	10s	3m39s	21.9× faster

Key takeaway: Gemini 2 was the slowest of the five tools on all three tiers, and the gap is widest over a network. It was also the only tool whose time did not respond to scope: when ~115 GiB of Photos libraries was excluded from the USB-C scan, DuoBolt, Czkawka and dupeGuru each shed close to the 227 seconds that reading those bytes costs at the volume’s measured rate of 542 MB/s, and Gemini 2 shed none.

Feature Comparison

Feature	DuoBolt	Gemini 2
Platforms	macOS, Windows	macOS only
Minimum OS	macOS 11 · Windows 10	macOS 10.10
Pricing model	Free tier · $34.99 Standard or $64.99 Pro — one-time, 2 seats, macOS + Windows	$19.99/yr (App Store) · one-time €44.95 for 1 Mac, €66.95 for 2, €99.95 for 5 (macpaw.com) · Setapp from $9.99/mo
Sold as a subscription	No	Yes, from $1.95/mo — alongside a perpetual license
Hashing	BLAKE3, named and documented	Not disclosed
Match type	Exact byte-for-byte, plus similar photos	Exact + similarity (fuzzy)
Adjustable similarity	Yes — five bands, Identical to Loosely similar	Not disclosed
Opens RAW files	Yes — CR2/CR3, NEF, ARW, RAF, ORF, RW2, DNG and more	Not documented
HEIC / AVIF	Yes (Windows needs two free Store extensions for previews)	Not documented
Apple Photos library	Yes (macOS) — reads the library, removes to Photos’ Recently Deleted	Yes, with albums — cannot Trash from it directly
Explains its photo picks	Yes — every measure is named	No
APFS clone awareness	Yes	No
Scans `~/Library`	Yes	No (sandbox restriction)
NAS / network volumes	Yes	Times out at TB scale
Rescan cache	Yes — hashes and thumbnails, separate local and network thresholds	Not disclosed
Re-runnable scan history	Yes — each scan’s full setup is stored and can run again	No
Safe deletion	Trash, archive, or copy	Via system Trash
Protected folders	Yes	—
Recovers permanent deletions	Yes — rebuilt from a byte-identical copy, with the original dates and tags	No — only what is still in the Trash
Public benchmarks	Yes	No
Account / telemetry	None	MacPaw / Setapp account

Where Gemini 2 wins on this table. It runs on Macs going back to macOS 10.10, where DuoBolt needs macOS 11. And inside the Photos library it knows about albums, which DuoBolt does not read: a scan there is about the photos themselves — their copies, their imports, their favorites and edits — not about where you filed them.

On price, like for like. Both tools sell a perpetual license, so compare the same thing: two machines, bought outright. Gemini 2 is €66.95 for two Macs — roughly $77. DuoBolt Standard is $34.99 for two seats, and DuoBolt Pro, which adds the entire look-alike photo engine and AI Curation on top, is $64.99. Our most expensive tier costs less than their two-Mac license, and a DuoBolt license covers Windows machines as well — Gemini 2 is macOS only.

MacPaw prices checked 16 August 2026 on the macpaw.com store; euro figures converted at approximately 1.16 USD/EUR. Both vendors change prices, so check the current figure before relying on it.

When to Choose DuoBolt

You scan large libraries or NAS

Over SMB, DuoBolt scans 1.09 TiB of music and video in 10 seconds against Gemini 2’s 3m39s. That tier is decided by network latency, and it is where the two are furthest apart.

You need to scan ~/Library or other system folders

Gemini 2 runs sandboxed and can’t access ~/Library — a major source of duplicate caches, app data, and stale build artifacts. DuoBolt scans these areas without restriction.

You want honest disk-space accounting

DuoBolt detects APFS clone groups (e.g., cp clones, Time Machine snapshots, build caches) so the “recoverable space” number reflects what your disk actually frees. Gemini 2 doesn’t distinguish clones from real duplicates.

You are not only on a Mac

Gemini 2 is macOS-only. DuoBolt runs on macOS and Windows with the same engine, the same results, and one license covering two machines.

When to Choose Gemini 2

You’re cleaning up an Apple Photos library by album, inside the Photos app itself
You’re already a Setapp subscriber and the bundle works for your workflow
Your scans are small, local, and well-structured (no NAS, no ~/Library, no cross-platform needs)
You prefer Gemini 2’s animated Smart Selection experience over a precision-first interface

Why DuoBolt Performs Better at Scale

Gemini 2 is optimized for the median Mac user’s photo and music libraries. DuoBolt was designed around three constraints that consumer-grade scanners don’t optimize for:

Per-root parallelism — DuoBolt keeps every CPU core busy across multiple scan roots simultaneously, instead of serializing through one filesystem traversal. This is what makes the 11.66× gap across a source tree of 1.69 million files.
Streaming, chunked I/O — reads overlap with hashing so the CPU never waits for slow disks. On NAS volumes where latency dominates, this is 10 seconds against 3m39s.
No sandbox — DuoBolt is distributed directly (not via the Mac App Store) so it can scan ~/Library, external drives mounted by other users, and system locations without permission walls. Gemini 2’s sandbox is a UX win for casual users and a hard ceiling for power users.

On top of speed, DuoBolt is APFS clone-aware: when files share storage at the filesystem level (Time Machine snapshots, cp clones, Xcode caches), DuoBolt reports both “recoverable” and “total” so you know what your disk will actually free. Gemini 2 does not offer a clone-aware figure, so a space estimate that includes cloned files will overstate what deleting them frees.

For full methodology, hardware details, and the third-party comparisons, see the benchmark page.

Match Type: Exact vs Similarity

The single biggest difference between the two tools isn’t speed — it’s what they consider a “duplicate.”

Gemini 2 mixes exact matches with similar matches: photos taken seconds apart, music files re-encoded at different bitrates, near-identical exports. Useful for cleaning up a photo library, dangerous if you mistake a “similar” match for an exact one.
DuoBolt runs two engines and keeps their verdicts apart. Duplicate files are flagged only when they are byte-for-byte identical, proven by cryptographic BLAKE3 hashing — see why exact matters. Look-alike photos are a separate engine that never uses the word identical: it groups by what the picture shows, tells you how tightly the group matched, and ranks each group while naming what it measured.

The difference is not that one tool does similarity and the other does not. It is that DuoBolt will not call a similarity verdict a duplicate.

If you’ve ever clicked “delete” on a Gemini 2 group and worried whether the matches were actually identical, that’s the gap. DuoBolt removes the worry by removing the ambiguity.

Getting a File Back After It Is Gone

Gemini 2’s safety net is the Trash: files go there, and you drag them out again if you were wrong. Empty the Trash, or delete permanently, and that is the end of it. MacPaw’s own FAQ says so.

DuoBolt’s safety net is not the Trash, and does not depend on it.

Every operation writes a journal row per file before the file goes away: its path, size, modified and created dates, permissions, extended attributes, and the BLAKE3 hash of its contents. To bring a file back, DuoBolt looks for a file still on disk with that same hash — a surviving copy of the very bytes — copies it to the original path, and puts the recorded identity back on it.

That is a reconstruction, not an undelete, and the difference cuts both ways:

It works after the Trash has been emptied, and after a permanent delete, which no Trash-based restore can offer.
It needs a surviving copy. Remove the last file holding those bytes and they are gone; DuoBolt says so on the screen rather than offering a button that would fail.

Three rules keep it honest. Eligibility is decided by content hash, never by group, so a photo is never rebuilt from a look-alike neighbor. The dates, tags and permissions come from the recorded original, never from the surviving copy, which has its own. And nothing is ever overwritten: if something occupies the original path, the file lands beside it as name (restored).ext.

This is in every tier, including the free one. See History and restore.

Full Benchmark Results

All three storage tiers, compared against Gemini 2, Czkawka, dupeGuru and Duplicate File Finder, with full methodology.

View Benchmarks →

Exact duplicate file finder

Why DuoBolt only flags byte-for-byte matches — no name shortcuts, no fuzzy matching, and what that verdict does and does not claim.

Download DuoBolt

Free to scan on macOS and Windows, with a free tier that also cleans.

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