Oh, thanks!
Btw, will the difference in GHz matter? I have no idea what that means haha but the two I'm comparing have 1.8 (Air) and 2.5 (Pro), is that going to be noticeable?
Ghz is a measure of clock speed. For a given CPU design, you can use Ghz as a way of relating the performance of the CPU between two CPUs of the same family.
Suppose you have two Core i5 CPUs. One's rated 2.0Ghz, one's rated 2.5Ghz. This means that the 2nd one is 25% faster than the first one. (because it's got 25% more Ghz)
Then suppose you have a Core 2 Duo (old) and a Core i5 (newer). Both at 2.0Ghz. Comparing the two is less meaningful because while they have the same clock speed (Ghz), they're different CPU designs.
The simplest analogy I've heard is one of row boats. You've seen the old boat races where there's a guy beating the drum, and the rowers row to the beat of the drum, right?
The drum is clock. Beat faster == increase in clock speed == increase in number of times you row/calculate.
The rowers are the core. Different sets of rowers perform differently, just like differently designed cores perform differently.
So 1.8 vs 2.5 (assuming both Core i5) means that the Pro is 38% faster when it comes to pure CPU (photoshop and video renders are all CPU). While this sounds like quite a bit, know that most of the time, the CPU is already done and waiting for the user. So when you're talking about the computer doing PS filters that take 3 seconds on the Pro, they'll take about 4 seconds on the Air. You save a little over a second in this case. Paying more to shave off a second doesn't sound so grand anymore, eh?
And in general, most actions never take that long to begin with. Hence why I say from experience, that the performance really shouldn't matter that much to you.
The only time I really notice the difference is during the final render for videos. In this case, I'd be running the system at full blast for an hour. I'd save maybe a half hour when comparing against my old system. It'd be nicer to have it faster, sure. But then again, it'd not like I sit there and watch the machine during the batch. I'd go off and get lunch or something and it's done by the time I get back.
If I were in a big studio and my renders needed to be done same day and ready for broadcast, then yes, I'd buy the biggest most awesome machine ever. But, I'm not time constrained like that. And as a student, I'd venture to assume you're not time constrained like that either.