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SysTools EML Converter software box

SysTools EML Converter Performance Comparison

SysTools EML Converter processed 18,233 EML files (7.68 GB) to PDF in 13 minutes. Previous version took 6 hours 18 minutes 7 seconds for the same job.

Across 11 export formats, SysTools EML Converter finishes in a median of 9.2 times less time. Exports range from 4 minutes 7 seconds for MBOX to 14 minutes 45 seconds for PST on the test machine.

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Median time gain

0x10x20x30x
9.2x
Median time gain across 11 formats

Total time for 11 formats

Previous version16 hr 54 min 26 sec
SysTools EML Converter1 hr 45 min 37 sec
15 hr 8 min 49 sec saved
Same 18,233 EML files, same 11 formats

Quick numbers

29.1xBiggest gain, EML to PDF
4 min 7 secQuickest export, EML to MBOX
18,233EML files (7.68 GB) in every test

Watch EML Converter Finish Before Previous Version

Select an export format and press Replay. Both bars use real test times, sped up so you can watch them finish.

Previous version
Finished 6 hr 18 min 7 sec
SysTools EML Converter
Finished 13 min
29.1x
faster, saves 6 hr 5 min 7 sec

Test Setup for the EML Converter Comparison

Every result below comes from a folder of 18,233 EML files that totals 7.68 GB. You see time, output size, file count, CPU and memory for 12 export formats.

18,233
EML files
7.68 GB
Source size
12
Export formats
1.99 GHz
Processor
11.9 GB
Memory on the test machine
Sep 2026
Test date

Previous version supports 11 of these formats, so ZIP has no earlier result to compare.

EML Converter Speed Comparison by Export Format

SysTools EML Converter beat the previous version in all 11 formats that both versions support. EML to PDF shows the biggest gain at 29.1 times, and EML to TXT follows at 20.0 times. EML to MSG shows the smallest gain at 2.8 times, which still saves 26 minutes.

Previous versionSysTools EML ConverterGreen bar length shows the share of previous time.
PDF
EML to PDF97% less time
29.1x
Previous6 hr 18 min 7 sec
New13 min
Saves 6 hr 5 min 7 sec
TXT
EML to TXT95% less time
20.0x
Previous2 hr 29 min 24 sec
New7 min 29 sec
Saves 2 hr 21 min 55 sec
HTML
EML to HTML91% less time
11.3x
Previous1 hr 30 min 46 sec
New8 min 3 sec
Saves 1 hr 22 min 43 sec
MBOX
EML to MBOX91% less time
10.7x
Previous43 min 56 sec
New4 min 7 sec
Saves 39 min 49 sec
CSV
EML to CSV90% less time
9.9x
Previous1 hr 16 min 6 sec
New7 min 41 sec
Saves 1 hr 8 min 25 sec
EML
EML to EML89% less time
9.2x
Previous1 hr 19 min
New8 min 37 sec
Saves 1 hr 10 min 23 sec
MHT
EML to MHT77% less time
4.4x
Previous42 min 44 sec
New9 min 41 sec
Saves 33 min 3 sec
JSON
EML to JSON75% less time
4.0x
Previous39 min 46 sec
New9 min 58 sec
Saves 29 min 48 sec
EMLX
EML to EMLX74% less time
3.8x
Previous30 min
New7 min 54 sec
Saves 22 min 6 sec
PST
EML to PST66% less time
3.0x
Previous44 min
New14 min 45 sec
Saves 29 min 15 sec
MSG
EML to MSG65% less time
2.8x
Previous40 min 37 sec
New14 min 22 sec
Saves 26 min 15 sec
ZIP
EML to ZIPNo previous result
New
New5 min 25 sec
Previous version has no ZIP result

Speed Gain by Export Format

Time Taken by Export Format

Previous versionSysTools EML Converter
Export FormatNew VersionPrevious VersionSpeed Gain
EML to PDF13 min6 hr 18 min 7 sec29.1x
EML to PST14 min 45 sec44 min3.0x
EML to MBOX4 min 7 sec43 min 56 sec10.7x
EML to MSG14 min 22 sec40 min 37 sec2.8x
EML to CSV7 min 41 sec1 hr 16 min 6 sec9.9x
EML to JSON9 min 58 sec39 min 46 sec4.0x
EML to HTML8 min 3 sec1 hr 30 min 46 sec11.3x
EML to MHT9 min 41 sec42 min 44 sec4.4x
EML to TXT7 min 29 sec2 hr 29 min 24 sec20.0x
EML to EML8 min 37 sec1 hr 19 min9.2x
EML to EMLX7 min 54 sec30 min3.8x
EML to ZIP5 min 25 secNot supportedNew

Add the 11 formats together and previous version needed 16 hours 54 minutes 26 seconds. SysTools EML Converter needs 1 hour 45 minutes 37 seconds for the same exports.

EML to ZIP is new. SysTools EML Converter finished it in 5 minutes 25 seconds, and previous version has no ZIP result to compare.

Output Size and Files Converted by Format

MHT output is the largest at 13.1 GB from a 7.68 GB source. EML, EMLX and MBOX outputs stay close to the source size at 7.59 GB, 7.59 GB and 7.58 GB. CSV, JSON and TXT outputs land near 5.5 GB.

Output Size by Export Format

Previous versionSysTools EML ConverterSource 7.68 GB
Export FormatFiles Out, NewFiles Out, PreviousOutput Size, NewOutput Size, Previous
EML to PDF18,23218,2216.33 GB5.46 GB
EML to PST18,23218,2206.00 GB4.77 GB
EML to MBOXNot recordedNot recorded7.58 GB4.98 GB
EML to MSG18,23218,2175.96 GB5.10 GB
EML to CSVNot recorded18,2235.52 GB4.79 GB
EML to JSON18,232Not recorded5.51 GB4.34 GB
EML to HTML18,23218,2335.59 GB4.66 GB
EML to MHT18,23218,23313.10 GB10.40 GB
EML to TXT18,23218,2165.51 GB4.39 GB
EML to EML18,23218,2137.59 GB6.22 GB
EML to EMLX18,23218,2157.59 GB6.21 GB
EML to ZIPNot recordedNot supported6.75 GBNot supported

SysTools EML Converter wrote 18,232 files in every format with a recorded count, and one source file did not convert. Previous version wrote between 18,213 and 18,233 files in the formats with a recorded count.

Source for every row is 18,233 EML files and 7.68 GB. Not recorded means the test log has no value for that cell, and Not supported means previous version has no ZIP export.

CPU and Memory Use During EML Conversion

SysTools EML Converter used 100% of the 1.99 GHz processor in all 12 tests. Previous version used between 21% and 56%.

Previous versionSysTools EML ConverterCharts cover the 11 formats that both versions finished

Average CPU use

41%Previous versionof the processor
100%SysTools EML Converterof the processor

Average memory use

8.7 GBPrevious version73% of 11.9 GB
6.9 GBSysTools EML Converter58% of 11.9 GB

Memory by export format

CPU by export format

Export FormatCPU, NewCPU, PreviousMemory, NewMemory, Previous
EML to PDF100%21%7.2 GB5.6 GB
EML to PST100%34%9.5 GB10.0 GB
EML to MBOX100%47%6.5 GB9.8 GB
EML to MSG100%34%7.5 GB7.9 GB
EML to CSV100%56%6.0 GB9.6 GB
EML to JSON100%56%6.3 GB7.8 GB
EML to HTML100%32%6.9 GB9.7 GB
EML to MHT100%42%6.4 GB7.6 GB
EML to TXT100%41%6.1 GB7.5 GB
EML to EML100%54%7.3 GB10.4 GB
EML to EMLX100%34%6.3 GB10.2 GB
EML to ZIP100%Not supported6.9 GBNot supported

Memory use stays between 6.0 GB and 9.5 GB on the 11.9 GB test machine. SysTools EML Converter used less memory than previous version in 10 of 11 formats.

EML Converter Test With 22,650 EML Files

SysTools EML Converter processed 22,650 EML files (5.65 GB) to PDF in 16 minutes 51 seconds in the software window. Previous .NET engine needed 1 hour 21 minutes 52 seconds for the same files.

EngineSource SizeOutput SizeFiles ExportedTime TakenSpeed Gain
Previous .NET engine5.65 GB4.62 GBNot recorded1 hr 21 min 52 secBase
New engine, console mode5.65 GB4.54 GB22,64715 min 44 sec5.2x
New engine, software window5.65 GB4.54 GB22,64716 min 51 sec4.9x

Speed gain is 4.9 times in the software window and 5.2 times in console mode. SysTools EML Converter exported 22,647 files in both new engine tests, and the output came to 4.54 GB against 4.62 GB from the .NET engine.

Test date is 23 July 2026. Output format is PDF.

Want the export steps? Open the SysTools EML Converter Software Guide for Windows or visit the SysTools EML Converter page.

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