ill try to say what parts affect gaming in any form:
your processor has to calculate things that happen in the game. like: peoples location,your location,where particles are flying etc.
your graphics card takes that information and creates a picture for the monitor,a fast graphics card can turn these:"informations" faster into an image.which means generally more fps.
your ram speedwise doesnt do much,BUT the amount of ram is important when having many things loaded at once,like many entities,many players all these things have to do with capacity. which is why there is no real need for more then 8gb of RAM in a normal gaming system.
your hard drives/ssd's speed can improve loading times in games. that includes: loading screens but also texture pop ins which happen when many textures need ot be loaded at once from your hard drive to be shown inside the game,but it takes a long time to do so.
now from the top:
CPU speed is important because if the cpu isnt fast enough,the graphics card needs to wait for your CPU to calculate the frame. which will yield a so known: "bottleneck" where 1 component cannot run at its maximal/optimal speed because a diffrent component is too slow
there u go