It is common knowledge that using a mouse and a keyboard naturally allows for more precise movement and controls, which, in most cases, gives PC players an advantage over controller players. So when it comes to Modern Warfare 2, console players may be inherently faced with a more challenging experience.
The hardware you'll need to meet the Call of Duty Modern Warfare 2 recommended system requirements isn't that much higher. Crafting a team of 12GB of RAM and a processor as powerful as the Intel Core i7 4770 or AMD Ryzen 5 1400 will help maintain higher minimum and maximum frame rates.