For casual gamers, the bare minimum is still 8GB but there is plenty of evidence to suggest that the upgrade to 16GB will ensure smoother gameplay.

For serious gamers with mid-range to high-end hardware, we're almost at the point where we'd say 16GB the the minimal acceptable amount of system memory. Of course, as we said earlier, if you've invested over $1,000 in your GPU and SSD combo then chances are spending just shy of $200 to secure a decent 16GB DDR4 memory kit probably isn't something you're going to think twice about. For GTX 1060 or RX 580 owners who've spent $200-$250 on their graphics card, dumping another $200 on DDR4 memory is something they're probably umming and ahhing about. If you're playing games such as Battlefield 1 or in particular Call of Duty WWII and you care about being competitive, then 16GB really is a must.

Alternatively, if you have a relatively high-end GPU such as the GTX 1070 or Vega 56 but play older, less memory-intensive games, then 8GB will no doubt be fine. But again, for these newer titles you'll ideally want 16GB.