Clint is correct. I can allocate resources to whichever domains I need to in the most effective manner. So, of course, I allocate the most to the domains that are paying the bills around here. When the resources get stretched, I have it set to deny access to the lower priority sites so that the higher priority ones can still keep on operating.
I had 470 simultaneous logins at my main site. Not sure what was going on there but that most certainly caused the bogging down across the server.
That's the way it goes, I guess.