Benchmarks — measured on public corpora
Measured, not marketed.
Every number is from a real run you can reproduce — no illustrative estimates. Where 7-Zip or WinRAR still wins, we show it.
46% smaller
On versioned / redundant data
Two Linux kernel versions in one archive: 135.1 MiB vs 7-Zip’s 249.8 MiB — and extracted 4.5× faster.
~4× faster
Extraction on many files
The kernel and real-world sets extract in ~14–17s where 7-Zip takes ~67–76s and WinRAR ~52–65s. Compression at -m6 runs ~1.3–1.7× faster than 7-Zip -mx9 too.
~1–3% behind
Ratio against 7-Zip
With the same 64 MiB dictionary, 7-Zip -mx9 still compresses smaller than Slim -m6: 1% on unrelated source trees (172.7 vs 174.7 MiB) and 3% on text (enwik9: 204.8 vs 211.1 MiB), taking 1.3–2.6× as long. Shown because a benchmark you can’t trust is worthless.
Cyan = best in that column for the corpus (whichever tool wins). Lower is better for size and time; higher for % saved. Archive size (MiB) is the ground truth. Slim -m2 and -m5 lie between their neighbors in archive size and compression time.
Dictionary (match window): Slim -m1 and -m2 use each block as the window (blocks of up to 16 MiB and 64 MiB, compressed independently); -m3 to -m6 use 64 MiB. WinRAR 64 MiB (-md64m), 7-Zip 64 MiB (-md64m; without it, -mx9 uses a larger default), ZIP 32 KiB (fixed by the Deflate format).
Measured on a Lenovo Legion 5 Pro — AMD Ryzen 7 8745HX (8C/16T), 32 GB DDR5-5200, NVMe SSD, Windows 11 Pro. Runs of 2026-10-04 (Slim Archiver 1.0.0, WinRAR, ZIP) and 2026-10-07 (7-Zip with a 64 MiB dictionary) · Median of 3 runs · Defender real-time scan off · AC power.
All times were measured with each tool’s command line (slimarch.exe for Slim Archiver). The desktop app runs the same engine; its times can be somewhat longer, and with Data Loss Prevention enabled (Enterprise) every file is scanned before it is compressed, which adds time.
slimarch — create encrypted archive