These benchmarks are from two years ago. The version of Cake used isn't even a stable release (1.2 RC1). Either way 1.3 has replaced 1.2 and is plenty fast for 99.99999% of sites.
Take with a grain of salt.
EDIT: yeah, pretty sure the original Yii benchmark is dated as the graph has older versions while the phpmark repo has slighlty newer ones ( http://code.google.com/p/phpmark/source/browse/#svn/trunk )
this and similar reports from others are the reason i don't use cake, though, and it seems like it would be in their best interest to get some newer information out there. (i made my choices years ago though)