I think fortex is correct in saying, "This is because the mag for a project is capped, you are essentially competing for magnitude against yourself." I'm new to Gridcoin, but I thought about this too. If someone has several powerful rigs and they put all of their resources into one project, their own RAC begins to work against them in the magnitude calculation.

One other observation regarding spreading around your computational resources. Unless you're spending a lot of time tracking who is coming into and out of a project and your RAC relative to everyone else, it would be better to have more than one project. That way if someone with a lot of RAC potential jumps into one of your projects (and you didn't notice), you aren't as negatively impacted because you've got other projects to sustain your overall account magnitude. It's akin to not putting all of your money into a single stock unless you're closely watching it each day. It's better to spread around your risk with multiple stocks (or projects in gridcoin) and play for the best average return.