Under most conditions for me.
- Gaming while light multi-tasking
-Youtube video on second monitor
-Teamspeak open
-multiple tabs open in Firefox
I see around 45 ish percent of ram used with 16 GB dual channel.
I could reduce this to under 40% relatively easily by not having as many background things running.
So even at that load, I "could" get away with 8 GB.
Is this on a new build/major upgrade?
Try real hard to get 16 GB.
IF this means budget issues on other must have parts, then get 8 GB.
It will still run fine under 99% of conditions.
If you get a single 8 GB stick, planning on getting a second one later, this will work, but it will obviously not be dual channel, and there will be a slight performance hit.
But not terrible.
Just make sure if/when you get a second stick, it is EXACTLY the same ram.
Another option is to get 2 4GB sticks, in a kit. Then buy 2 8GB sticks later on, and sell the 2 x 4 kit.
Short answer, yes you can get away with 8GB of ram with today's games.