I get consistent crashes using virtual textures. I've installed (the amazing addons!) jestr's Earth II and JohnVV's Moon, and I've found that after viewing a certain number of textures (by zooming or orbiting) I'll either get the Mac "spinning beachball" followed by a crash: "EXC_BAD_INSTRUCTION (SIGILL)" or textures will start going missing like in the screenshot below:

After I start seeing missing virtual textures, random program features stop working, menu items disappear (blank!), and a "EXC_BAD_INSTRUCTION (SIGILL)" is guaranteed if I continue.