Help me decide a laptop for computer science major

[Dhipz]

i want to buy a laptop that i will use for computer science major (entering this year) as well as light photoshop and a bit ot gaming. Im not sure whats the specs i need for cs major so heres what i think the best for my budget

LENOVO IDEAPAD 110-14ISK
- Intel Core i3 6100U
- Memory 4gb
- AMD RADEON R5430 2Gb

Lenovo IP 110-14AST
- CPU AMD A9-9400 2.4 Ghz
- RAM 4 Gb
- VGA AMD Radeon R5 2 Gb

HP 14 AN004AU / ASUS X454YA
AMD Quad Core A8-7410
RAM DDR3L 4GB
VGA AMD Radeon Graphics

The i3 and a9 are second hand but still have a warranty (about 8 months) and all of them have pretty much the same price (the a9 slightly cheap)

So from all of them, which one is better?

 

[laviniuc]

whichever you can easily add 4gb of ram to. and whichever you can easily replace the harddrive on. you're gonna want a ssd drive instead of whatever they come with. and you'll want 8gb ram instead of 4.