For games, the main role is played by the video card and processor. Try to install a high quality processor while the graphics card should be changed every six months. It is not entirely necessary to acquire the most expensive model because the price of the equipment usually decreases after the first month. Choice of manufacturer is solely a matter of personal preference in this regard.
Nowadays, modern operating systems are designed for a variety of applications. Therefore, they carry on doing a lot of unnecessary internal processes. There are plenty of special versions of Windows, where the number of "extra" stuff is kept to a minimum and the overall performance can significantly be improved.
Optimise your system with additional programmes. There are many "accelerators" and "optimisers", which are designed to work precisely with games. They will clear the memory, free up space on your hard drive and generally make your PC much more productive as far as gaming is concerned. Also, do not forget to regularly defragment your hard drive.
Download a programme called Game Booster. It is designed to optimise the laptop or computer for game play. This program will automatically disable all unused services and change the configuration of the operating system, which will greatly reduce the load on the processor and RAM.
It is very important that you update all the existing drivers for your graphics and sound card. This only takes a few minutes but can make a world of difference while playing games on your computer.