SFPack uses a so called lossless compression scheme to save diskspace or transmission time when sending a soundfont via email or ftp. Lossless means that the original quality of the sounds is preserved. There are so called lossy compression schemes (like MP3 or RealAudio) that can produce much higher compression ratios, but because they loose information during compression, are unusable for digital samples.
SFPack generally compresses files between 30% and 70% of the original file size, depending on the nature of the sound data stored in the soundfont. But this compression ratio is much better than can be achieved with any other program, cause SFPack uses it's own highly optimized compression routines for digital sound data
SFPack is about 3 times faster as sfArc V1.18 and about 1.5 times faster as WinZip V7.0. Also SFPack adapts itself to your current system load, so you can compress Gigs of samples in the background without bringing your system to a halt.
With its explorer like interface it's very easy to compress and inflate files the way you want.
SFPack is tightly integrated with the windows shell. With special commands in the popup menus for SFPack and SF2 files it's a snap to compress and expand files.