I have just placed order for a 200 mm fan (Cooler Master MegaFlow 200mm), and I was not sure whether to have a positive air flow for the fan or a negative one. As shown in the picture below I have the Thermaltake Overseer RX-I, which offers a fan on the removable side panel. If installed the fan will be centered right above the dual GPUs.
At the moment I have a net positive air pressure inside the case: the top 200 mm fan, the lower right 200 mm fan, and the dual 120 mm fans for the corsair Hydro H80 are all providing positive air pressure. The 120 mm fan in the bottom on the right of the PSU provides negative air pressure.
Any suggestions on the direction of air flow for the new fan I will be installing.