If the only difference is between the processors (assuming you leave everything else the same - harddisk, graphics card, amount of RAM, screen etc) then you will not notice a major difference, so I'd go with the cheaper one.
In practice the performance of a computer depends on a lot more than just the CPU speed and type. If you can, get an SSD instead of a harddisk, that makes a much bigger difference (because SSDs are much faster than harddisks).
Jesper de Jong wrote:If the only difference is between the processors (assuming you leave everything else the same - harddisk, graphics card, amount of RAM, screen etc) then you will not notice a major difference, so I'd go with the cheaper one.
I haven't searched for those specific processor models yet, but I had to make almost similar choice 2 years ago. I chose i7 because i5 had 2 cores and 4 threads whereas i7 had 4 cores and 8 threads. I think it would make fast context switches (maybe useful for Java GC?)
Definitely go for more RAM. If you're running VMs (or want to run heavy servers) you need all the RAM you can get, as 8GB really isn't enough these days if you want to do that kind of thing. So make sure your machine can take extra RAM later on (some boards are limited even though a 64-bit OS can take vast amounts of RAM), even if you don't install the extra memory straight away.
If you're getting a Windows machine, consider re-partitioning it and using a large chunk of your disk space for dual-booting with Linux, as it will give you access to a much wider range of tools for software development, and it's less resource-hungry than Windows. And it will mean you can code on Windows or Linux without the overhead of a VM.