Hi Liza and everyone else who came across this page looking for useful answers.
Here's a couple of things that others haven't quite grasped yet.
Firstly the name "Pentium" is now just a marketing term usually referring to Intels cheapest range of processors. Actual Pentiums came out in the 90's and were their main product line. But this is irrelevant.
The current generation of pentiums have come from the intel Atom architecture. These chips are super low powered, cheap to make, and came from the netbook era. They're great for things like chrome books etc, set top boxes, and tiny stick PCs like the Intel compute stick. Cool things, but not really fit for purpose when it comes to a personal use laptop/PC
As for performance, without going into to too much detail, the Pentium's per core processing power is around half of the i3, but it has twice as many cores. This might sound like they're about even, but bear in mind that most software DOES NOT deal with multiple cores. This means any single program is only going to use a single core. So it's going to run at half the speed on an the atom based pentium quad core, than it is on the i3. So the i3 is going to be a much better option all round.
Here's link to cpuboss which, while not necessarily a perfect apples to apples comparison, does give a pretty good idea of performance.
http
/cpuboss.com/cpus/Intel-Pentium-N3530-vs-Intel-Core-i3-4005U
Now. Ram.
Here's how I describe ram. Imagine your computer is an office. Ram is the size of your desk, where the hard drive is the filing cabinet in the corner. When you load something up (including windows itself) the computer goes to that filing cabinet, pulls out the files it needs and puts then on the desk for you to use. If your desk is too small, and gets full of stuff, the computer has to constantly go backwards and forwards to the filing cabinet to swap the files around, and this obviously takes AGES.
So you get more ram, which is like getting a larger desk. This is great and means that the computer has loads of space to have heaps of stuff open at once and will run nice and fast without having to go back to the filing cabinet all the time.
However, once you have a large enough desk, and you have enough space for everything you want to do, you could make that desk 10 times larger, and it wouldn't make a lick of difference. Once you have enough ram, adding more will make absolutely no difference.
There are another few factors here, ram is cheap (~$20 USD for 4gb) and very easy and quick to upgrade in any machine. 6GB would likely be enough for anything you need to do for now. Maybe down the track you need a bit more, but it's an easy cheap upgrade that any computer geek with their salt could do in a flash. This I think takes the ram off the table as the difference is negligible and the solution (to a problem that doesn't yet exist) is very easy.
Lastly, I want to talk about the elephant in the room. The hard drive.
The absolute best upgrade you could possibly do to any laptop, is to replace the hard drive with a solid state drive. These do the same job but 5-500 times faster! They have no moving parts, they use less power, create less heat, and are not susceptible to damage like a traditional spinning hard drive. Upgrading to an SSD is getting much cheaper now, and will absolutely change the way that you think about computers. If you put an SSD into your old Core 2 Duo laptop, it would outperform either of these new laptops in most general tasks. (obviously not in processor specific tasks). An SSD is THE BEST single upgrade you can do to any machine.
Hope this helps a few people out.