for us to be certain on where is the location of the problem we need to have your fully detailed pc (I.e cpu,gpu,ram,psu,cooling and temps) only them we could safely assume what the problem is.
as for the keyboard and mice.Keyboard
- what are you looking in it. are you looking for mechanical buttons\touch buttons\easily press able buttons\ durability\weight \lots of configarable keys for MMORPG games and etc.Mice
- to fit a mice perfectly for the user we need to know another few details. size of your hands,in what way you hold the mouse (fingertips\claws\grip) , what features you are looking for (fast response/high dpi/lots keys/weight managment/on the fly dpi control and ETC) and on what surface you are planning to use the mouse
also if you have any brand preference (for both mouse +keyboard) i.e Razer/ SteelSeries/ Logitech or any other company.
if you can answer most of this questions we would be glad to give you a good answer for all of your questions