Are they all going to be active under load at one time? Or all just running, but only a few loaded at a time? If it's the latter, they could share CPU resources, but they can't share RAM. Assuming you need a minimum of 4GB of RAM per VM (maybe more, no idea what OS you're running or what you're doing with them), that means 400+ GB of RAM. That means you're looking at Xeons, possibly multi socket systems.