When looking at the 7-Zip compression numbers, we were impressed with the improvement that was made over the course of a single OS release. In this test, for example, the Snow Leopard performance numbers were about 16% higher than that of Leopard.
Beyond the 7-Zip numbers, we also timed how long it took to compress a 2GB sample file using Gzip. Unlike the 7-Zip MIPS counting test, here it took roughly the same amount of time to compress a 2GB file under Mac OS X 10.6.0 as it did in Mac OS X 10.5.8. The MM1 system, however, came out slightly ahead with Snow Leopard.
For looking at the file encryption performance under Snow Leopard, we threw in the Java-powered Bork program to encrypt a sample file. Gosh, another massive performance improvement. The Bork File Encryption performance on the 2009 Mac Mini was about 25% faster under Snow Leopard!