Thanks for the kind words, guys, I really appreciate it! Fulcrum, you make some good points. I did not include version numbers because I felt they are constantly changing anyway. For example, seven of the apps were updated, and five of the 14 apps were upgraded in the past month, and in the last two days as I was finishing, WinZip released its Pro 10 beta. It turned out to be a timely review.
I did, however, use the latest version of WinRK, and the only reason I included it on the site was because of its excellent compression rate, of which I found at the site you listed, Maximumcompression.com. I also kept downloading the testing each program's latest release throughout the review. Version info could be easily added, but I made the decision to say "as of Fall 2005" and let readers review each program's history file to see what version was out in August/Sept 2005.
Early on, I found lots of resources at
Maximumcompression.com, and RJ, I did study Jeff Gilchrist's
excellent studies so I'd know what to expect,
but spending too much time there was distracting me from the real purpose of the review, which was to find the best archive program, not necessarily the best compression ratio. The latter was only one factor considered, albeit an essential one. The second reason is that I've no expertise with compression algorithms, and could not write intelligently about them without spending an extra month or longer researching for just that part of the review.
As you may have noticed, the section on 7z, RAR, and PPMd formats is cursory at best. Thus the resource links to compression sites listed in the left panel of the review. When you dive deep into the content of those sites, you're quickly impressed with the work those authors have done. There was no way I could replicate such exact tests, and as mentioned above, it was beyond the scope of this review.
Finally, you make another important point on settings within each program.
The only tweaks I made regarded compression levels — Normal, Fast, Max (some list it Ultra or SuperFast or Best) and nothing else for each program. I started flirting with dictionary sizes, but there was no way to standardize these settings across all the archivers tested because most did not allow users to change those settings. So I merely left them at the default settings and just changed compression levels for each format when archiving my test file.
My goal was to take each program and try to get the fastest archive I could, despite compression ratio, and then reverse that and get the best compression ratio I could, no matter the time. When you look at that comparative Excel grid, you'll see the fastest time I could get using any compression level for each app, and then the smallest compression ratio I could. Those two numbers are independent, not linked to each other. There was a direct correlation between ratio and time — the more you demanded from one, the less you received from the other, proving the saying:
you don't get something for nothing.
Thanks for the feedback! I'm grateful for it.
