I've done some testing on 2.82 MB (2.958.359 bytes) of data made using Eagle Layout Editor

Some filesizes:

552.380 bytes - WinRAR 3.30, max compression.
72.740 bytes - WinRAR 3.30, solid archive, max compression.
433.253 bytes - 7-Zip, max compression.
53.868 bytes - 7-zip, solid archive, max compression.

While these are some nice numbers, i don't think you should quit using your current archiver because of the huge hd's you can buy these days.

If you're going to use it for file distribution on the internet, this'll probably be the way to go. Consider using sfx archives. I've packed the same data using 7-zip (solid archive, max compression and sfx archive), the filesize of the sfx archive: 130.156 bytes.

My only question is: Can it decompress the new rar format? It's used quite a lot on the Internet these days

no idea, have never tried that, I usually try to decompress things with the formats own decompressor, as things like dissapearing files etc. can occur (like when a winrar'1' unpacking a winrar'2' file, files can be 'lost' ... without any warnings or anything)

I doubt it's possible to have a format that is 'the best', they're just good at different areas, a clear looser in one comparation can be a clear winner in another. So It's up do each and everyone of us to find what's best for the things one do mostly.

I've read it a while ago.

my point is ... at the beginning noone except the developers use it, by spread of word (or advertising for those that can afford it) the number of people that know of it and start use it increase ...

I will make everything I do with an alternative download with 7zip ... for those that use it ... and want to download it than much larger zips ... and dont want to pay for archieving software.

http://www.7-zip.org/

Released under the GNU LGPL, and windows versions is released at 7-zip.org, and there is linux/unix versions released by independent developers, at sourceforge...

Did some testing, and might aswell show you guys aswell ...

A .bmp file (5 409 656 bytes): (ineffective binary data )
7zip: 138 717 byte
ace: 176 664 byte
rar: 178 250 byte

A Nascar Racing 2003 replay file .rpy (2 061 808 bytes): (timebased binary position data, lots and lots of it)
7zip: 776 710 byte
ace: 913 870 byte
rar: 977 288 byte

A 14 327 592 byte WMV ...
rar: 14 276 427 byte
ace: 14 303 899 byte
7zip: 14 327 513 byte

Folder with 7 .mov files (24 985 235 bytes):
7zip: 24 387 159 byte
rar: 24 650 986 byte
ace: 24 697 607 byte

Mixed assortion of files (819 513 bytes): (My AC Cobra 289 for racer, wav and tgas mostly, and some other small files + an encrypted compressed archive)
rar: 277 481 byte
ace: 281 678 byte
7zip: 304 955 byte

The MySQL table files, 231 files in 7 folders  (6 519 878 byte):
7zip: 3 820 380 byte
rar: 3 833 965 byte
ace: 3 888 601 byte

A folder with 237 wav files (9 218 612 bytes):
ace: 5 404 720 byte
7zip: 5 585 183 byte
rar: 5 730 793 byte

A single large wav file (13 335 380 bytes):
ace: 11 061 374 byte
rar: 11 172 279 byte
7zip: 12 214 562 byte

A 3d object, in Lightwave format (1 246 606 bytes): (~ iff format)
ace: 322 384 byte
7zip: 337 751 byte
rar: 338 874 byte

PunBB 1.1.5 full pack (636 308 bytes):
rar: 90 055 byte
7zip: 92 310 byte
ace: 130 640 byte
zip: 201 007 byte (the downloaded file)

All these tests were made with maximum compression, and solid archive. (except Rickards zip, that may well use those settings aswell)

By the look of it 7zip is most effective when dealing with non-dense files, and when data comes in regular bursts, and doesn't like that much directory handling ... and rar seem to like things that's already packed together alot, ace seem to like audio files. ... it's not like it's done very scientific or something ... but I will make the switch, mainly due to the free application.

There's more to test that I really didn't feel like putting down more time on, and that's dictionary sizes, word sizes and things like that ... I used some basic values and when testing some on 7zip, it was mostly a few bytes here and there ...

All I know is that I will make the switch ...