7-Zip 4.58 alpha 1 for Windows 32 bit and x64 by Igor Pavlov

7-Zip 4.58 alpha 1 was released.

7-Zip for 32-bit Windows:
http://www.7-zip.org/alpha/7z458a1.exe

What's new:
- Small improvements in ZIP/Deflate compression.
- 7-Zip was compiled by new version of C++ compiler.

7-Zip 4.58 alpha was compiled by VC++ compiler from Windows Driver Kit (WDK). Some codecs now are faster and some codecs are slower. I need more information about the performance of new version. If the performance is poor, I can go back to old compiler (VC++ 6).

You can post some benchmark results here for 7-Zip 4.57 / 4.58. Just call:
7z b > res.txt
Write also some information about your CPU: CPU Type/Frequency.

Also you can compare another codecs (Bzip2/PPMD/Deflate/AES) using timer program:
http://www.7-zip.org/dl/utils/timer301.zip
To exclude HDD reading time from results you can run 7-zip two or more times with same file.

Note also that compression speed for Zip/Deflate in Ultra mode was improved in 7-zip 4.58. So it is faster than 4.57 by another reason.

Another question is compatibility with Windows 9x/ME and NT4.
If you have any compatibility problems, write here about them and write also information about msvcrt.dll in you system folder (version number and timestamp).

Forum: http://sourceforge.net/forum/forum.php?forum_id=45797
Homepage: http://sourceforge.net/projects/sevenzip/

Download:
Win32: http://www.7-zip.org/alpha/7z458a1.exe
Win x64: http://www.7-zip.org/alpha/7z458a1-x64.msi