That's truly impressive.
I retired my 2009 MacBook Pro Core 2 Duo 2.26 GHz a long time ago... although my 8 year-old uses my 2008 MacBook Core 2 Duo 2.0 GHz until I get him a new computer.
Which 2009 do you have? 2.0 GHz is a touch too slow for a ton of stuff but it works for basic web surfing. 2.26 GHz is a small but actually noticeable improvement as it's an increase in clock speed of 13%. I'd imagine 2.66 GHz would be another small but noticeable improvement with an 18% increase in clock speed over 2.26 GHz.
BTW, while the 2.0 GHz MacBook is on its last legs though with a dying battery and dead optical drive, everything it still OK with the 2.26 GHz MacBook Pro. Both still have their original batteries!