how to know if your computer can run a game or not before the download?

I know that the majority of people spend a lot of time in playing games, but the only problem that could face you and make you upset is that you can download a game and install it ; and finally doesn't work, why ? because your computer hasn't the minimum or the recommended system requirements .
So its a waste of time waiting the download to finish !!!!!
i have found the best solution that everyone can use it and know if his computer can run a game in a good condition or not.
it's a website called "systemrequirementslab" that allow you to choose the name of the game and it will give you all the information you need.

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