There isn't a huge difference between 2.4 and 2.26 Ghz. That's a .14 difference which is tiny.
So I doubt it's going to be any faster.
Woah woah woah... You are going from an Intel Pentium 4 2.4 SINGLE CORE processor.... and then going to a intel core 2 duo processor 2.26 ghz processor and you are saying that it is going to be a TINY difference? You have to look at FSB which your old single core is probably 400mhz and the intel core 2 duo is 1066mhz and comes with 2gb of DDR3 not DDR2 ram which operates at 1066mhz. Now from the ram alone I heard from DDR2 to DDR3 it operates 30 percent faster which helps for programs like video editing and such. And the processor matters too.
I am going out on a limb going to say that it is going to operate much faster and smother considering the OS and the intel core 2 duo processor upgrade from your old system.
got this from another website
they say that a 2.8Ghz P4 520 does their lame test in 5:05, the Core 2 Duo @ 2.13Ghz does the same test in 3:10, the P4 got 834 in 3DMark 06 while the Core 2 Duo got 1892, and for PCMark 05/CPU the P4 got 3522 while the Core 2 Duo got 5489
so doing the math on those numbers would say that the Core 2 Duo @ 2.13Ghz is 1.8 times faster then a P4 @ 2.8Ghz, and that's with the slowest Core 2 Duo, its not a Conroe
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So it looks like the intel core 2 duo is 2 times faster than the p4 of 2.8 which is better than your 2.4. so maybe even the upgrade you should see 2.5 times faster with the mac processor (2.26ghz) vs your p4 2.4 processor. I bet the gap would be even better in terms of being faster.