Wow, imagine if AMD got the money to buy SSE2 from intel, then wut.... Anyways, I am going to throw my input on this about the "feeling." I myself have a old skewl tbredb 1700+ at 2500mhz. My little bro has P4C 2.6c@3.6. Besides those, we have similar hardware, same HD, same vidcard (mine is sapphire 9800pro, his BBA), same moniter, same memory, different case, different cooling (im water, he is slk9whatever). When he comes over to LAN a bit, we never tested opening up applications at the same time to see speeds, BUT he always marvels at how my computer "feels" faster.
I don't know exactly what that means, im drooling over his system and how much more FPS it gets outta games. But I do notice the lag time is smaller with my system. 3.6Ghz vs 2.5Ghz and mine feel's faster opening up things like Outlook, dbl clicking on a word document and loading up word, browsing along the internet, booting up time.
All in all, next time he comes over, maybe we will clock it (and record video on my nice new canon a70). But this post is funny since I never thought about feel even though every time my bro comes we talk about it. That's why I had to post this. Maybe this can be somewhat scientific.
The only reason he got the p4c is because I told him to LOL (he doesn't know too much about comp hardware) and he thinks somehow I tricked him to get a system that is worse than mine for higher price LOL. I show him his benchies and mine and then he is finally satisfied.