From my experiences you need a few megabytes of gpu memory to render a console, atleast this was the case from my previous job, but were talking around 7-8mb or so. No idea wether or not they had some wierd setup which caused this, they were working with some really wierd setups doing math on GPUs and what not, but the onboard gpu from your motherboard would do more then well, and you dont need to connect a monitor or anything, just the vram is needed.