I'm building a rendering pc on a budget of 600$ and I'm going on used market. My build for now is 2 xeon x5650 with supermicro X8DTL-3F mobo 24gb of ddr3 1333 ram EVGA 80+ gold full modular 750wats power supply and I do not know what I should get to cool these cpus. And do I need a graphics card? I'm working with keyshot, autocad, solidworks.