brotli vs zstd performances comparison         

brotli vs zstandard

Fast compression: Brotli, Zstandard comparative speed, performances test

br vs zst compression and extraction speed
Fast compression: Brotli, Zstandard comparative speed, performances test




Test the new fast compressors Brotli (Google) and Zstandard (Facebook) at different compression settings to determine what compression level and compression / decompression speed the two standards are capable to offer as general purpose file compressors.

  1. Find out what is the more efficient algorithm between Brotli and Zstandard in terms of speed and compression ratio, at different compression settings ranging from minimum to maximum. Which one is the fastest compressor / decompressor? Which ones compresses better? Which algorithm scales better at different compression levels?
  2. Compare Brotli and Zstandard performances with classic reference compression formats as 7Z, RAR and ZIP at standard compression levels.

Software settings

Benchmarks are conducted on Windows 10 2009 64 bit.
PeaZip 7.2.0 64 bit is tested for compression and decompression in following formats:
  • 7z 19.00 (64 bit)
  • Brotli 1.0.7 (64 bit)
  • Zstd 1.4.4 (64 bit)
The reference application for ZIP and RAR formats performances in this test is WinRar 5.8 64 bit.

Hardware settings

Notebook with Intel Core i7-8565U CPU, 4 physical cores with hyper-threading (8 logical cores), 8 GB RAM
System disk 512 GB PCIe NVMe SSD, NTFS filesystem

Compression formats compared in this benchmark

  • 7Z file format Open Source archive format by 7-Zip, providing high compression ratio, tested at default compression level, default LZMA2 algorithm, from PeaZip
  • Br (Brotli) compression format created by Google for providing very fast compression and decompression, tested from fastest to maximum compression level from PeaZip
  • RAR file format (RarLabs RAR5 revision) proprietary archive format providing better compression that ZIP using PPMd algorithm, tested at default compression level from WinRar
  • ZIP file format widely used archive format, tested at default compression setting (with Deflate algorithm) from WinRar, which qualified as the fastest zip compressor in previous batch of PeaZip's compression benchmarks
  • Zst (Zstandard) compression format created by Facebook, multithreaded Zstd compressor, providing very fast compression and decompression, tested from fastest to maximum compression level from PeaZip

Input data

Benchmark input contains 43 files in 4 directories for total 1.22 GB (1,318,000,857 bytes), composed by well known reference files representative of different data structures, widely used for compression benchmarks:

Compression / decompression speed, performances

Benchmark methods

Benchmark input data is saved to system disk (PCIe SSD) and compressed to system disk, same partition, separate directory; the resulting archives are then extracted to separate directory on same (system) disk/partition. The use of a fast disk support is meant to minimize the impact of disk speed on Brotli and Zstandard performances.

Each compression and extraction test is repeated 10 times to get an average value; size is expressed in MB, time in seconds.

Brotli and Zstandard requires to consolidate the multiple input files of the benchmark into a single TAR file, the overhead of tar / untar operations is about one second (about one second performance penalty to tar, about one second to untar) and needs to be taken in account when comparing with results of classic compressors in 7Z, RAR and ZIP formats.

Following compression levels were tested:
  • fastest, minimum compression supported by the format, defined as 0 in Brotli, 1 in Zstd
  • default, defined as 3 for both compressors
  • high and very high compression levels, intermediate settings between default and maximum, chosen as 5 and 7 for Brotli, and as 9 and 15 for Zstd
  • maximum compression level, defined as 9 for Brotli and 19 for Zstd
As current implementation of Zstandard is multithreaded while Brotli is not, the same test were conducted also on Zstd (Zstandard) compressor with -T1 option which disables multithreading, to provide also a meaningful comparison on the single thread. PeaZip by default uses the -T0 option enabling automatic multithreading using all suitable CPU resources.

As Zstandard window size is variable, depending on the compression level, while Brotli uses fixed window size, a second test batch was conducted in order to compare the two algorithms in closer conditions - while the first batch of test aims to a simple out-of-the-box performances comparison.
In this second test, window size was fixed to 128 MB (2^27 bytes) for both algorithms, with --large_window=27 option for Brotli, and --long=27 for Zstd, which also runs this test series single threaded with -T1 parameter.
Having the two algorithms running with same windows size and same number of threads allows to better understand efficiency of Brotli and Zstandard on the basis of reasonably similar cost of computing resources, and choosing a such large window size challenges the ability of the algorithms in preserving speed performances and efficiently scale the compression ratio.

No extra compression settings were used to fine tune the compression, neither for Brotli nor for Zstandard, compression was defined exclusively setting the compression level parameter. Both algorithms features plenty fine-tuning options, which are out of the scope of this benchmark.

For classic file archiving formats ZIP, RAR, and 7Z, it was tested only the default compression level, to highlight typical compression / speed tradeoff commonly offered out of the box. Testing the entire performance spectrum of those algorithms against Brotli and Zstandard is out of the scope of the present analysis, but is a possible future topic of interest.

Brotli vs Zstandard benchmark results tables

Out-of-the-box compression and extraction times in seconds, size of resulting archive in MB, the lower the better for all columns.

Compression level
Compression time (sec)
time (sec)
Archive size (MB) Compression
 -T0 (sec)
single thread -T1 (sec)
time (sec)
Archive size (MB)
Brotli -0 / Zstd -1
Brotli -3 / Zstd -3
Brotli -5 / Zstd -9
Very high
Brotli -7 / Zstd -15
Brotli -9 / Zstd -19

Fixed 128 MB window size for both algorithms:

Brotli --large_window=27
Zstandard -T1 --long=27
Compression level
Compression time (sec)
time (sec)
Archive size (MB) Compression
 -T0 (sec)
time (sec)
Archive size (MB)
Brotli -0 / Zstd -1
Brotli -3 / Zstd -3
Brotli -5 / Zstd -9
Very high
Brotli -7 / Zstd -15
Brotli -9 / Zstd -19

For reference, results of traditional compressors group, at default compression settings:

Compression format
Compression time (sec)
time (sec)
Archive size (MB)
WinRar, default
WinRar, default
PeaZip, default

Compression speed benchmark results

The curve of the performances for the two algorithms shows that, out of the box, Zstandard is generally faster and provides better compression ratio than Brotli.
Only in the point of high compression level (-5 for Brotli, -9 for Zstd) Brotli provides a marginally better compression ratio (353 MB versus 355 MB) and the speed advantage of Zstandard is reduced.

For minimum and default compression settings, Zstandard is both faster and compresses better than Brotli, this hold true running Zstd single-threaded (-T1 parameter).

For very high and maximum compression settings, Zstandard again provides better compression ratio in less time than Brotli, but at top compression levels multi-threading is clearly a key factor for Zstd performance. Single threaded compression times, comparatively, are significantly worse than Brotli ones.
Maximum compression ratio reached with Zstandard is significantly better than Brotli one, with 302 MB (24.04%) vs 322 MB (25.64%).

brotli vs zstd compression ratio

For reference, fastest implementation of fastest traditional compression format (ZIP in WinRar, at default compression level) completed the test with a result strikingly similar to Brotli at default level (-3): 15.6 sec for zip compression vs 15 seconds, 16 taking in account adding files to tar beforehand, for Brotli, with very similar output size (408 for Brotli vs 407 for ZIP).
However, at default compression level Zstd outperformed Brotli and Zip, providing a better compression (398 MB) nearly four time as fast - or nearly twice as fast when launched single-threaded.

and 7Z, at default compression level, reached compression ratios comparable or better than top ones provided by Brotli and Zstandard ar maximum compression level - RAR slightly better than Brotli but worse than Zstandard (318 MB vs respectively 322 and 302 MB), 7Z reaching best compression with 293 MB otput archive.
Also, notwithstanding the similar compression ratio provided, compression times are shorter for Rar and 7z at default compression level than Brotli / Zstandard at maximum compression level, proving the algorithms in use being less efficient that PPMd and LZMA2 for working at those levels of compression.

Compression speed with same window size

The second batch of tests, running with window size fixed to 2^17 (128 MB) for both algorithms, shows a sizeable improvement of compression ratio for both Brotli and Zstd.
The decrease in speed is moderate for both algorithms, except for Zstandard at fast compression levels which is significantly slower with 128 MB wide window than with automatically size window size.

Comparing Brotli and Zstd with same window size, and both running single-threaded, shows Zstandard providing a better compression at each compression level, being faster than Brotli al default, but not at minimum, compression level and slower at higher compression levels.
Performance differences are more evident at extremes (faster and slower compression levels), while at an intermediate point of the graph ( Brotli -5 / Zstd -9) both speed and compression ratio differences are less pronounced - similarly that in the previous batch of tests.

brotli vs zstd compression with same window size

With a 128 MB window size both Brotli and Zstandard fares better in comparison of classic compression formats
Zstd -1 provides same compression of ZIP (default) in half the time, and Brotli -5 and Zstd -9 come close to RAR (default) compression in slightly more than half the time: those numbers shows both algorithms have excellent potential for fast to intermediate compression.
Zstd -15 and Brotli -9 rivals 7Z at default compression level, and Zstd -19 compresses the output to 20 MB smaller size, but both algorithms are significantly slower confirming not being optimal choices for high compression tasks.

Brotli / Zstandard comparative at fastest compression settings

Focusing on fastest and default compression levels, clearly the most interesting settings for projects targeted to high performances, the benchmark shows a sizeable advantage for Zstandard in terms of compression ratio and speed, over Brotli.
With fastest compression settings, multithreading (while still important) is not a critical factor for Zstd speed performances, as even single threaded Zstandard completes the test faster than Brotli.
This is the opposite of what seen at higher compression levels in previous chart, where Zstd still provides better compression but at cost of more computing power - being significantly slower than Brotli when running single threaded.

brotli vs zstd speed comparison

Using the same window size for both algorithms, 128 MB, and running them single threaded, Zstandard at minimum compression level provides a consistent advantage over Brotli (407 MB output vs 473 MB) but is 3 second slower.
At default compression level, Zstandard is both faster and compresses better than Brotli.
At the first high compression setting (Brotli -5 vs Zstd -9) the compression ratio performances are very close (with a slight output size advantage for Zstd), but Zstandard is slower than Brotli, with the trend continuing on this side of the graph with single threaded Zstd being slower than Brotli with same window size, but providing higher compression.

brotli vs zstandard performances with same window size

Extraction speed comparison

Extraction speed slightly slows as compression level increase (with the exception of Brotli at minimum compression taking half a second more than at default level) but generally - unlike the compression speed - it remains remarkably constant from lower to highest compression levels.

Extraction from classic archive formats highlights 7Z as the format allowing fastest decompression, followed by RAR and then ZIP: and both Zstandard and Brotli always remains competitive for decompression speeds with the ones of mainstream archiving formats, even taking in account the one second overhead penalty to untar the content after decompressing the .br / .zst archives.

Comparing Brotli and Zstandard extraction speed, Zstandard provides the best decompression performances for every compression level, being uniformly about 40% faster than Brotli- except for extracting the file compressed at minimum compression level, where Zstd is about twice as fast as Brotli.

For Brotli, decompression of archives created with fixed 128 MB window size is constantly slightly faster for each compression level (excluding for the minimum), than decompression of standard archives.
For Zstd, extraction times remains quite similar for the two series of tests, standard archives and ones created with 128 MB fixed window size, without one type showing a clear advantage, unlike for Brotli. A slight trend can be inferred of extraction times of second group being comparatively slower for lower compression and faster for higher compression levels.

brotli vs zstd decompression speed

Conclusions: Brotli, Zstandard comparison

Brotli, Zstandard performances comparison

Zstandard outperforms Brotli at minimum and standard compression levels
, which are likely the most useful range for fast compressors aiming to operate in real-time. Both speed and compression ratio results are better for Zstandard in this range of the benchmark.
The speed advantage is reduced, but still very noticeable, when comparing the two current implementations of Brotli and Zstd running single threaded.

Increasing the compression level, Zstandard algorithm exhibits more flexibility allowing to reach better compression ratio than Brotli, but this come with severe performance penalty that makes single-threaded Zstd slower than Brotli.
Running Zstd with multi threading option enabled more than makes up for the difference, allowing Zstd to run faster than Brotli in this range of the benchmark, this of course means allocating more computing resources to Zstandard: while on a desktop system this is a positive factor, on a server needing to allocate resources for multiple concurrent instances, the advantage of Brotli in completing the high compression tests faster per thread may be preferable.
The lack of a multi-threaded implementation of Brotli for this benchmark limits the ability to compare the two algorithms more closely.

Running a second batch of the test single threaded and with same window size for both algorithms (128 MB in current benchmark) confirms the trend already seen in the previous test batch.
Using same window size Zstandard provides better compression results at lower compression levels, operating faster at comparable compression ratio - even if Brotli is faster at minimum compression setting at cost of consistently reduced compression ratio.
The performances levels out at an average level (Brotli -5, Zstd -9), and then, at higher compression levels, Brotli is faster than single-threaded Zstandard which in turn provides better compression.

Decompression is always faster for Zstandard than for Brotli, with a consistent advantage (around 40%) in the entire range of benchmarks.
Both algorithms exhibit the capability to keep the extraction time reasonably constant decompressing files created ranging from minimum to maximum compression levels.

ADDENDUM: in the Maximum compression benchmark it is now available a direct comparison of Brotli and Zstandard at maximum compression settings, in terms of compression ratio and compression / decompression speed.

Conclusions in brief:

Which is the fastest compressor, Brotli or Zstd?

Zstd is overall faster, but it is due to its multi-threading capabilities that Brotli lacks.
Running in a single thread, Zstandard is faster for low compression levels, slower at high compression levels.

Which is the faster decompressor between Brotli and Zstd?

Zstandard decompression is always faster than Brotli ones.

Which format provides best compression, Brotli BR or Zstandard ZST?

Zstandard compression ratio is consistently better than Brotli ones, looking at the curves of speed / ratio performances tradeoff the two algorithms provides quite overlapping results only at an intermediate point (Brotli -5 / Zstd -9) otherwise ZST-compressed files are significantly smaller than BR-compressed files in all remaining points.
With a large window size, fixed at 128 MB for both algorithms, compression is clearly improved for both algorithms, but the curves of speed / compression ratio shows the same dynamics.

Which algorithm scales better at different compression levels, Brotli or Zstd?

Zstandard scales better on the entire spectrum of results, providing either better and faster compression at minimum / default settings, and better maximum compression ratio at maximum settings, but the latter advantage comes at expense of more a more computing intensive data compression strategy.
With both algorithms using same window size (128 MB) and running in a single thread, Brotli provides a minimum compression faster that Zstandard (but inferior for compression ratio) and Zstandard provides a better maximum compression (but slower).

Syntetic test results by compression level:

Zstd fastest compression settings compared with Brotli

This is a clear win for Zstd, providing 22 MB smaller output in less than half the time, speed advantage is consistently reduced in single thread mode.
With same window size (128 MB), Brotli surpasses Zstandard in single-threaded speed, but output size advantage for Zstd increases to 66 MB.

Zstd default compression settings compared with Brotli

This use case shows a consistent advantage for Zstandard, creating a 10 MB smaller output in a quarter of the time needed by Brotly to complete same test, and still twice faster running in a single thread. Using same window size for the two algorithms, both size and speed advantages for Zstandard are reduced.

Zstd maximum compression settings compared with Brotli

Zstandard beats Brotli for maximum compression by a 20 MB margin, comparing the speed of the two algorithms in this case Brotli (which is single threaded) is slower if compared with multi-threaded Zstd result, but faster if compared with single threaded result.
With a fixed 128 window size for both algorithms, Zstd preserve its 20 MB difference on output size, and while Brotli remains faster its speed advantage is proportionally reduced over Zstandard.

Brotli and Zstandard compared to 7Z LZMA2, RAR PPMd, ZIP Deflate

Compared with classic Zip format, Brotli at standard level operated at compression / extraction speed, and compression ratio very similar to fastest Zip implementation, taking in account tar/untar overhead to operate as general purpose archiver.
Zstandard at same compression level shows a clear advantage in all those aspects over Brotli and Zip / Deflate.

Comparison with Rar format shows neither Brotli nor Zstandard are specialized for operating at such high compression ratio: RAR operating with PPMd at default compression level completed the test in times that are intermediate to ones of high and very high level for both algorithms, but results are comparable with those at the much slower maximum compression setting.
Zstandard at maximum compression level is still capable of beating Rar PPMd compression ratio at default level, but being 3.5 times slower, showing it is not optimized for this usage.

7z format at default level outperforms maximum compression attainable with both Brotli and Zstandard at maximum level, while remaining significantly faster, showing its LZMA2 algorithm it is more fit for high compression tasks. LZMA2 scores the smallest output size in this test, and the result is not matched even by other classic compressors.

Brotli and Zstandard are not a match for RAR PPMd or 7Z LZMA2 in the range of strong data compression, even increasing window size to 128 MB, providing a poor tradeoff between compression gain and speed decrease when running at highest compression settings: even if very flexible and efficient, quick data compression remains the primary field of application for both algorithms.

Bottom line of the comparison with classic file archiving formats is that Brotli and Zstandard are excellent choices for fast / very fast compression, and as general purpose archiving format are viable alternatives to Zip in terms of speed / compression tradeoff.
Of the two, Zstandard clearly stands off for this case of use, surpassing Deflate and Brotli in efficiency even when single-threaded.
Increasing windows size to 128 MB, fixed size, quite large for those algorithms, does not excessively impact on speed and in turn offers welcome improvements in compression ratio for both functions, with Brotli -5 and Zstd -9 providing results almost comparable to RAR (default) compression in significantly faster times, showing excellent potential for tasks requiring intermediate compression - but still not competitive for high compression tasks.

Read more about how to create Brotli compressed files, how to create Zstandard compressed files, how to use Brotli and Zstandard compression in 7z archives, and how to optimize file compression speed.

Synopsis: Fast compression benchmark. Comparison of Brotli versus Zstandard formats performances at different compression settings. BR vs ZST compression and extraction speed comparative test. Comparison of Brotli and Zstandard speed with 7Z LZMA2, RAR PPMd, and ZIP Deflate algorithms for fastest compressor and decompressor.

Topics: fast compression benchmark, Brotli vs Zstandard benchmarks results, decompression speed test

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