Yes, it's normal. take a look at game size, ram take as much as they can so that your game wouldn't take a very long loading between maps, and prepare files to load so that you wouldn't feel huge laaaaaag. If you have doubts use anti-virus full scan and if you wish you can try this scanning tool, it's free and helped me a lot few times, removes spam viruses (it's not a commercial, and I do not recommend to buy anything from them) https://www.malwarebytes.com/adwcleaner/