16GB of ram is ridiculously cheap these days, especially when looking at the cost of other components, such as the GPU. I have 12GB, and run dangerously close to maxing it out when I run more than 8 clients. IMO for a serious boxing PC, 16GB would be the recommended amount. 8GB dimms aren't that expensive, so one could feasably get 2 dimms, leaving 2 available slots for future expansion, should the need arise.