Modern games will use pagefile more often when low on ram. You don't want that. Hell, even 980 Ti with its 6GB video framebuffer is recommended 16 gigs by
Nvidia.
32 gigs is a good amount of ram today, I say. 16 gigs is my recommended minimum for the budget gaming builds today. 8 gigs you will be asking for trouble/stutter/etc. If not today, but soon enough.
SSD can help when low on ram, however... So if you can't max out your RAM, get a fast SSD instead. At the very least.
P.S. Tomb Raider with very high textures already uses more than 8 gigs of ram @ 1080p. It will use less if you only have 8 gigs of ram, though. Compromise here, compromise there. To hell. More RAM is always better. I know when I upgraded from 16 > 32 my pagefile activity decreased dramatically, during gaming, etc.
This is all true for Windows 10 x64 Pro v1511.