It's nowhere 2-3x faster, 5-30% at best depending on the task.
It's also minimum of 25% more expensive on cheapest spec and 100% more just for CPU.
Nobody is arguing here which is faster, the i5 surely is but again as said before, if you don't need that extra then might just as well keep the money in your pocket, cheaper ram and motherboard could bring that 630 spec even another 25-30quid lower.
It will be already 5-6x faster than the p4.
So, the question here is really simple, yes that 630 spec is more likely to be enough for you, but if you want maximum performance, then I guess I'd go for i7 if you're already spending that money and want fastest stuff, don't forget to grab a good cooler too if you're going with the i5 or i7, any of those at less than 3.8ghz is a waste.