WINRAR 4.20is
a powerful archive manager. It can backup your data and reduce the size
of email attachments, decompress RAR, ZIP and other files downloaded
from Internet and create new archives in RAR and ZIP file format.
Changes in RAR compression RAR general compression algorithm is
optimized for better utilization of several processor cores. While some
speed gain is possible even in single processor mode, best results are
achieved in multi-core environment. Speed gain depends on data type and
average file size. Several cores are utilized more efficiently when
compressing large files. WINRAR 4.20 had to increase memory
requirements to achieve higher compression speed. General RAR
compression algorithm allocates about 120 MB comparing to 40 MB in
WINRAR 4.20. WINRAR 4.20 text compression algorithm
cannot utilize several CPU cores efficiently, so its performance in
multiprocessor environment is much lower than for general algorithm.
Also its decompression speed is much lower than in general algorithm
regardless of CPU number. So we decided to disable the text algorithm by
default. If you need maximum possible compression ratio for plain text
data regardless of speed, you can enable the text compression in
“Advanced compression parameter” dialog. Press “Compression” button on
“Advanced” page of archiving dialog to access it. You can also change
this option permanently in default compression profile; In the command
line mode the text compression can be enabled with much switch. “Fastest” (-m1) compression mode also
supports several processor cores now. In 4.11 it could use only a single
processor core. WINRAR 4.20 general decompression algorithm speed is
slightly improved,though not same extent as RAR compression. RAR
decompression is not able to use several processor cores, so its
performance does not depend on a number of cores. Changes in ZIP
compression: now ZIP compression supports
several processor cores resulting in noticeably higher performance in
multi-core environment. Single CPU ZIP compression is also faster than
in 4.11; Memory use for ZIP compression is increased to about 15 MB. Recovery volume creating and processing
can use several CPU cores resulting in higher speed. Though, typically
hard drive seek speed is a limiting factor for recovery volumes, so this
gain is most noticeable when working with solid state drive. Now the
allowed value for -mt switch is 1 – 32, not 0 – 16 as before. “Find
files” command can search data in 7-Zip archives. Previously “Find
files” did not support .7z archive format. Windows 2000 is not supported
by WINRAR 4.20 and WINRAR 4.20 self-extracting modules anymore. “Save current settings” button in
“Advanced SFX options” dialog is now available only when converting an
existing archive to SFX. Options saved with this button are applied only
to convert to SFX operation. If you create or update SFX archive, only
SFX options stored in default compression profile are used. Options
saved in “Advanced SFX options” dialog are ignored for these operations.
