On the "Ramblings of a web guy" blog by Brian Moon, there's a good look at some benchmarks run with PDO, normally versus with the "turbo button" as talked about by Wez.

So, a while back, I did some tests with the mysql, mysqli and PDO extensions. In those tests, I found PDO to be much slower for selects than mysql and mysqli. Half as slow in fact.

So, I decided to try Wez's trick of emulating prepared statements to see how PDO did. The results were interesting. Not sure if these are the "fair comparisons" that Wez wants to see, but I gave it my best shot.

His first set of stats was pretty close to his originals back when he first tested, and the second set of tests (with the "button" on) seem to be a bit hit and miss on the performance upgrade using this method.

I ran this several times. Maybe Wez or someone that works on PDO can shed some light on this. Seems like it would be tough to keep track of when to use this flag and when not to.