"Either machine will do the job. The larger cache will mean the CPU will more often be able to get the data it's working on from cache, rather than having to reach out to slower RAM. How much difference will that make? That depends on the programs you run, but it's unlikely to make a huge difference on average. The faster FSB means that when the CPU does have to reach out to RAM, it gets the data a little quicker. How much difference will that make? That depends on the programs you run, but it's unlikely to make a huge difference on average. The clock speed difference makes a more predictable performance difference, at least if you're running CPU-bound tasks.
All in all, I'd say the two are pretty much equivalent for most uses. If you were doing large calculations that consume 100% of the CPU for long periods of time, or which couldn't quite fit in 1MB of cache but fit in 3MB or... then it would matter. As it is, spending the extra $200 isn't going to make much difference at all. Honestly, if you're going to spend some extra money, I'd focus on spending it on better physical build quality, getting a machine that is durable and reliable.
If the machines don't have enough RAM, that's another place where it might be worth putting a few more dollars."
"I have a laptop with a T4300 and 4GB of RAM in it and I use it basically for the same things that you do (a Dell Inspiron 1545, if you're interested - crappy screen resolution; otherwise excellent machine). The specs on the Pentium are perfectly adequate. I see no difference, for development and productivity tasks, between that machine and my Core 2 Quad workstation (similarly specced to that P8700, but with two more cores).
One thing that MAY matter to you as a developer is that the Pentiums do not have the extra hardware virtualization bits that the beefier Core 2 chips do. That means, no Virtual PC on Windows 7, and VM performance in other software (VirtualBox) will be somewhat more sluggish.
If that doesn't matter to you, and you won't be doing any heavy tasks with the machine or trying to game with it, keep the $200."
