Hardware question: dual or quad core?

Hey people,

I'm planning to get a new notebook which will be primarily used for RoR
development. I'm not sure whether to get a i5 (dual core) or i7 (quad
core) cpu. I did a google search and stuff and couldn't really find any
benchmarks or something like that about multi core support of Ruby/RoR.
Does anyone know soemthing about it?

Btw. I'm running quite cpu demanding scripts that take up to 30 minutes
to run pretty often, that's why I need to know if a i7 would get the job
faster done than a i5 cpu.

If you are doing development on a single machine it is not just a
issue of Ruby being able to take advantage of the cores but the other
applications that you will be running. The database, the editor, the
OS itself. They all need CPU. If the system is swapping things in and
out because you don't have enough RAM then the number of cores you
have becomes a non issue.

So cores, the more the better. Ram, the more the better. The question
is how much can you get away with (unless you have very deep pockets).
I used to do Rails development on a Macintosh 12 inch G4 Powerbook
with 1Gb of ram running OSX, PostgreSQL and Textmate.

Why do these scripts take a long time to run? What is your CPU usage
when they run, how about disk / network usage? Page swaps?

Find out where the bottleneck on your scripts is and that should give
you some idea what resource needs to be boosted (at least for your
existing configuration).

Well, at the moment I'm on a Core2Duo and 3GB of RAM. CPU usage is ~90%
and RAM alltogether 2.0 - 2.5 GB used.

I'm planning to go on 6 or even 8 GB the only question remaining is
whether it's gonna be a i5 or a i7.

If you have only one script running use a I5.
If you are Running several scripts in parallel, use a I7

I had an i7 mbp. I just bought a mbair and due to the fact that it
uses flash media for storage it feels about a third faster at most
rails dev tasks I throw at it. For instance my cucumber suites run
about a third faster than my i7! Even parallels starts up and shuts
down faster.

Working on large Photoshop files has the i7 leading. But that's a
small part of my usual workflow. I'm loving the new mbair by a long
shot.