Monkey's Audio - a fast and powerful lossless audio compressor

Compressor	Efficiency^*	Time for Album (650 MB)	Compression: Size of Album (650 MB) / %
Monkey's Audio 3.90b1 (high)	222.9	2.1 min	348.3 MB / 53.6%
Monkey’s Audio 3.90b1 (normal)	221.6	1.7 min	353.9 MB / 54.5%
Monkey's Audio 3.90b1 (extra high)	218.0	4.1 min	342.5 MB / 52.7%
Monkey’s Audio 3.90b1 (fast)	211.6	1.5 min	369.9 MB / 56.9%
LPAC 3.03 (extra high – not random access)	211.1	5.0 min	348.5 MB / 53.6%
RKAU 1.07 (fast)	210.9	5.4 min	347.4 MB / 53.5%
WavPack 3.8b (high)	207.7	2.1 min	369.1 MB / 56.8%
FLAC 0.1 (default)	207.2	2.9 min	363.7 MB / 56.0%
RKAU 1.07 (normal)	203.0	9.8 min	347.6 MB / 53.5%
WavPack 3.8b (fast)	197.6	1.2 min	392.3 MB / 60.4%
LPAC 3.03 (fast)	196.7	1.6 min	388.4 MB / 59.8%
WavPack 3.8b (normal)	196.2	1.7 min	388.1 MB / 59.7%
Shorten 3.1	194.8	1.9 min	388.2 MB / 59.7%
RKAU 1.07 (high)	191.5	24.0 min	348.3 MB / 53.6%
RAR (Winrar 2.70, max with “–mm”)	169.3	8.0 min	400.9 MB / 61.9%
ZIP (Winrar 2.70, max)	42.5	2.9 min	591.3 MB / 91.0%

Note: several "second-tier" lossless compressors have been excluded from this comparison because they are no longer being developed and they don't really compare with the ones listed. These include WaveArc, WaveZip, and Perfect Clarity Audio, and a few others.

* Efficiency tries to evaluate the trade-off between speed and compression. The idea is to analyze how much "bang" you get for the time you wait while compressing. If you wait a long time but don't get good compression, that's poor efficiency. If it goes super fast, but you don't get hardly any compression, that's bad efficiency too. The idea is to try to strike a good balance between speed and compression. Obviously, rating efficiency is somewhat subjective because it depends on how long you're willing to wait for extra space savings... hopefully you'll agree that this equation is at least somewhat fair. (Mathematically, efficiency can be described: [Efficiency] = ([MB Saved]¹⁶ / [Seconds])^(1/16) )