How fast is Quad-core compared to Dual-core?

When the CPU is running flat out:

2.2 x 4cores = 8.8 GHz running

2.8 x 2cores = 5.6 GHz running

That is a simple comparison. But there are other improvements that are harder to predict, due to access speeds of the internal caches and RAM access speed.

The CPU is not always running flat-out, but scale it to 50% and you still have the sames ratios.

If you want a discussion of raw CPU power, we can do that. Even though the Quad is 600MHz slower than the Dual, note that each core can handle two threads, so the Quad is capable of doing 8 things at the same time, compared to 4 for the Dual; twice the amount of work. Does this translate to better performance? Depends on what programs you are running. Adobe was one of the first developers to do parallel processing and multithreading, so Photoshop will see the 8-thread capability and exploit it. Other programs from other sources may not be as smart.

But computers are not just the CPU. In your case, it would seem that your workflow will involve lots of graphics. The 13" models have "shared video memory", meaning that the CPU and the GPU battle it out for access to a common pool of RAM, with a corresponding performance hit. The 15" and 17" models have dedicated VRAM and heftier GPUs, meaning a faster graphics response. Note also that the 2.4GHz 15" model has 1GB of VRAM and an even faster GPU.

Lastly, as a graphics professional, have you experimented using the ultraglossy display in real world environments? I, for one, find the reflections excessively tiring on the eyes and have never owned a glossy screen computer in my life, even though I am not in the graphics business.

Nice points. Courcoul.

The 15 inch would be twice as fast as the 13 inch because quad-core is twice as fast as dual-core.

Heed Courcoul' advice on the glossy vs antiglare screen choice. I have two MBPs, one glossy and one anti-glare. The former is quite acceptable in IDEAL conditions, The anti glare is far more practical and the few serious photographers I know prefer it due to claims of superior color fidelity.

If Photoshop is on your agenda, the 15" is the proper choice.

Ciao.

I bought a 15 in anti-glare high-resolution (1680x1050) from the refurbished list (http://store.apple.com/us/browse/home/specialdeals/mac) to get the high-end finishes and a $300 savings off new.

I liked the better resolution, the non-glare, the better graphics, the larger screen.

That is one man's opinion, though.

Heck, for graphics work I'd recommend the 17"! But not everyone and their wallet are amenable to that aircraft-carrier-sized "portable" and its cost. So the 15" is an adequate compromise.

Words of warning:

• Buying SSD and RAM from Apple is akin to a visit from the highwaymen. Buy the stock option and upgrade from third party alternatives at a fraction of the cost.
• AppleCare warranty extension, if desired, is needed only after the base warranty. But terms state that said warranty has to be in effect. So, buy AC in the last month or so of regular coverage, invest the money in the meantime.
• Screen, CPU and GPU are non-upgradeable in portable. So be sure to get the biggest, meanest, newest you can afford so the computer wards off obsolescence as much as possible.