I have been woundering does a better Graphics Card and a better Pentium make your renders look better? Like sharper etc…
No.
In fact the graphics card does not affect the renders in any way at all.
Howver a better CPU means things will render faster, so you will be able to increase the render quality settings (OSA, render size, raydepth, number of AO samples, etc, etc). And a better graphics card means you will be able to model more complicated meshes without the UI slowing to a crawl.