Difference between i3 and i5 processor?

I'm looking to buy a Microsoft Surface Pro 3 and I want to know the difference between the i3 and i5 model as well as the processor difference. The price difference between the two is £200 so I don't really wanna buy the i5 version unless i need to in order to have a good experience with the Pro 3. Also I'm not a photo developer or anything I'm a student who will be using this as a tablet and mainly as a laptop for essays and write ups. Thank you Core i3-4020Y - special low performance i3.
low speed score 2183
https://www.cpubenchmark.net/...u_list.php
Processor Graphics Intel® HD Graphics 4200
Graphics Base Frequency200 MHz
Graphics Max Dynamic Frequency850 MHz
approximates hd 4000 graphics processor

This £250 laptop outperforms it
http://www.saveonlaptops.co.uk/MCC2NUK-Lenovo-Essential-B50-70_1733226.html

Core i5-4300U
score 3750. Graphics hd 4400

Surface Pro 3 keyboard was annoying to me. No way I would use a 12" screen and thin no-feedback keyboard to write college papers.
http://www.saveonlaptops.co.uk/Products/cat/Laptops/refine/46565~148010%2446565~144496%2446562~144410%2446564~148014%2446562~144409%2446562~177347%2446562~177349 It's all graphics. For the reason you described, I wouldn't bother as you wouldn't notice a difference and I suggest you go for i3 purely for the price. The only time you will need i5 is if you are wanting to play graphic-demanding games. I5 is a better processor that i3 as it process fastest and cool down easily The difference is some features which is I doubt you will use and slightly higher clock. So Go for the i3.

It's all graphics. For the reason you described, I wouldn't bother as you wouldn't notice a difference and I suggest you go for i3 purely for the price. The only time you will need i5 is if you are wanting to play graphic-demanding games.

I5 is a better processor that i3 as it process fastest and cool down easily

The difference is some features which is I doubt you will use and slightly higher clock. So Go for the i3.