People buying computers don't understand the difference between memory and storage, so as long as you've got your 250GB (pronounced "gee-bees") on the box, you're sorted. It's like fitting bikes with cheapo bottom brackets.
I'm not sure I follow your 250 GB reference. I'm asking about the RAM not the storage. The element that aiui the active / current data is stored as is being used, dynamic memory of you get my meaning (I don't know the correct terms so making my own up). The dynamic RAM is one factor in the computer performance. If it's too low the processor can't use its full processing power. My understanding is 4gb for basic use such as Internet surfing, basic word processing, streaming films, 8gb for more performance such as larger spreadsheets, multiple apps, etc. Then for more demanding applications even more might be needing (video editing and cad I guess).
So I assume the 250gb reference is the memory used to store the os, files, photos, music, etc. What I want to know is related to factors affecting performance such as processor and RAM.
Unless I'm mistaken 4gb RAM isn't well matched with a core i5 processor. There's an i5 chip with 4gb RAM and 256gb ssd or 1tb hdd instead. Then there's an i5 chip with 8gb and 256gb ssd and another with i3 chip, 8gb and 256gb ssd. The performance of the second should be the best but out of the other two I don't know. Would higher RAM on a lower speed chip be as good as a low RAM with a better chip?
Of course ultimately the real question is whether a laptop with core i5, 4GB RAM, 256GB SSD going to be good enough? Is the RAM a bit low? The reason being I've seen that there seem to be more 4GB RAM around at places like Currys and other main retailers. The one described above is within what I really wanted to spend and basically the same laptop except with twice the RAM is a lot more money to buy.