This is a late 2013 Mac Pro with defective FirePro D300 graphics cards.  Apple offered a repair program for the D500 & D700 models but for some reason abandoned those who purchased the D300 model.  I guess you don't become the richest company in the world by standing by your products...This computer randomly beachballs and locks up whenever it engages in "taxing graphics computations" such as displaying simple, text based webpages....  rendering it usless as a computer.This sale was a rip-off - straight up theft.