FreeArc is an open-source file compression utility which is popular for its highest compression levels. FreeArc uses LZMA, PPMD, TrueAudio, Tornado and GRzip algorithms with automatic switching by file type, and also uses set of filters. FreeArc works 2-5 times faster than best programs in each compression class while retaining the same compression ratio; from technical grounds, it's superior to any existing practical compressor. You can use any external program as compressor or filter as easy as internal ones, with Precomp, ECM, CCM(x), PPMonstr, Durilca, LPAQ, UDA and PAQ are already preconfigured in arc.ini as shipped
Excellent interface, may not be for a beginner. Integrated well with other freeware and Windows 7 from an install to a remote drive.
LOW compression, almost the same as any other less sophisticated program. I decided to try to see what I could do with archiving a small section of my digital library. The test subject was a batch: 2520 full picture quality scans of books in PDF format, in 47 subfolders. The unpacked volume= 10.4 Gb. With 7zip 64 I ended up with a folder= 10.2 Gb, with Freearc I achieved a folder volume of 10.1 Gb. Wooptie-doo. I understand that compressing these types of files is not crazy effective, I expected WAY more from a program with hype all over the web. Now, with a volume= 10.1 Gb + the program itself is approaching the original unpacked volume. This may work for you but is useless to me.
If you have a huge volume of text files, simple spread sheets, etc. this may be your ticket. But if you have anything of quality, and actually worth backing-up, look elsewhere.
I compressed a 7,2GB random file collection using the "best compression" settings in WinRAR. After 37 mins, I was left with a 4,22GB .rar file. I did the same using the (basic) "maximum compression" settings in FreeArc. It took about 15 mins more, but the resulting file is only 1,73GB! I've yet to encounter a compression software (7zip and Winzip included) capable of such high compression.
Compressing a file is very resource-heavy. I suppose it's less resource-heavy for lower compression rates, but I haven't checked.