I came across this digest of mac computer benchmarks today. For the uninitiated the benchmark used here was GeekBench which measures raw processing and memory power. Hard drive speed, graphics card performance, and other factors which come into play in the real world are not taken into account with this benchmark, so for instance the MacBookPro and MacBook score similarly even though real world performance may differ. Even so, this provides a useful point of reference which will correspond best to the speed a computer can process raw files to TIFFs.
http://www.primatelabs.ca/blog/2008/04/mac-performance-april-2008/