It also depends on whether you want to resell the games or just play them. I know that Windows XP (I know, I know....) can run many DOS floppy-based games just fine. Therefore, keeping an old Pentium II machine doesn't accomplish much if you're just looking for playability.
If you're looking to play the "latest and greatest" though, you want a newer system. I'm not really a gamer, so I may be wrong, but I wouldn't want to build a basic computer that barely plays the game I want. If I'm going to plop the money down for a game like GTA V, I would want the full, immersive experience, not frame drops and lagging from a machine that can do it.
Computers are like cars. We remember the good times of the past, but we tend to forget how far we've come....









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