i have also seen that they are using 16 gb ram instead of 8 that i have, could that be it?
it depends on the game or program they're running. it could also be that they have dual channel memory, which is faster in every way. but if your game stutters, i'm pretty sure it is because of your cpu. a ryzen 5 2600 is a very good and affordable option. you could buy one for about 110 to 140 dollars.
these are my specs:
CPU: AMD Ryzen 5 2600 Six Core Processor
GPU: XFX RX 580 8GB (as good as a gtx 1060 6gb)
RAM: Kingston HyperX 4GB DDR4 3200mhz (2x)(dual channel)
SSD: Crucial BX500 240GB
HDD: some 500gb toshiba thing i had laying around (stores all my games, not my important files)
MOBO: Asrock A320M-HDV R3.0
PSU: Cooler Master Masterwatt 650
now you have an idea of a stable, mid-end system without bottlenecks. you shouldn't just grab an old hard drive and shoot it inside your new system though, that was just me being the stupid person i am. but what did you expect from a 14 year-old, lol.