MMMm 300w PSU? You might want to check on those cards for the power. Normally when you go to include a decent video card you need more then a generic 300W (normally I seen best to be 600W). But as it is a mini tower, you can be limited on what you can get (maybe reason they sold it off so cheap?) because the mounting location / size of the case limites what powersupplies / and GPUs will fit in it. Take your dimensions inside the case and make sure stuff will fit too!