the thing with CPUs is that clock speed really isn't a measure of performance at all. if you take 2 chips of the exact same CPU model with different speeds then yes, one will be faster than the other, but if you try to compare 2 different types of CPU (even by the same manufacturer), it's an absolutely worthless measure. Intel tried to pretend for a long time that higher clock speeds were better, as their competitors were making CPUs that were faster at lower clock speeds (this is why AMD rate a chip something like 5200+ at 2600MHz - they're saying it'd be the equivalent of a 5200MHz pentium 4), then Intel trapped themselves by their own "higher clock speeds are better" marketing crap, physics prevents clock speeds getting much higher than they are now without generating obscene amounts of heat. but yeah, the newer chips, such as core duo or even it's single core equivalent, are much much faster at lower clock speeds than CPUs 2 or 3 years ago. people just have to get out of the mentality of "higher clock speeds are better" that Intel pushed for years
as for RAM, more RAM is almost always better, especially if you want to run a lot of programs at the same time. you will probably get some speed boost out of using 4GB instead of 2GB, more noticeable if you're likely to have a lot running at once. i run with 2GB currently and seem to be doing mostly fine, although i want to upgrade to 4GB soon, sometimes there are too many programs competing for resources even for 2GB to handle on my system.
