I was doing hunts mid-day EST last Friday (10 a.m. to about 12 a.m), and A ranks were derendering there were so many people. Eventually, the mob would get pulled by people creeping up and face pulling it as they try to keep it rendered on their screen.

my computer's specs are:
Windows 7 Pro 64-bit
i7-2600K quad core @ 3.4GHz
32 GB RAM
nVidia GeForce GTX 570