Processor Speed (now new problem)

I doubt you could measure a difference. Overall computer speed depends on the chipset (the "glue: that interfaces cpu to the rest of the machine), RAM speed, amount of RAM, HDD speed, internet connection speed, etc.

 

The new ones have far more power than your 2.4GHz model, even though they have a lower base clock speed. They are quad core, have hyperthreading (each core can act like two), and turbo boost (the clock speed will go higher if the application you are using would benefit from it), so in fact you are buying a faster computer, even with the 2.0GHz vs. 2.4GHz.

 

if you are choosing between the 2.0 and the 2.2 of the new models, also note that buying the 2.2 gets you a better graphics card, which will be worth it if you use your laptop for gaming or more graphically demanding applications like aperture or final cut. if you aren't a heavy user of those types of applications, the 2.0 will still be a massively sufficient upgrade

 

is there a BIG performance boost from th 256mb vidoe card vs the 1gb video card?

 

Substantial, but only with applications that utilize it.

 

the 2011 2.0, 2.2 and 2.3GHz models are quad-core (4x) whereas your 2.4GHz model is dual-core (2x). Thus, going from 2.4GHz dual-core to 2.0GHz quad-core, you'll see an immense performance boost. For example: the geekbench score for your 2.4GHz CPU is around 2600/4300 (integer/Floating point), whereas the geekbench score for the 2.0GHz quad CPU is around 7400/14500 (integer/Floating point).

 

Which one did you decide to get in the end?

 

This.

The 2.2 is the sweet spot IMO on the 15", get the 1GB VRAM, but don't waste the $$$ going to the 2.3. Do RAM and SSD on your own for far less $. The AG and Hi-res = goodness, if you have the $.

 

It might or might not be depending on if they have any stock left from before lion. But even if you do get a SL one you can get lion for free from apple at their up to date page.