add one more case fan or no?

[Paulius_3]

Hello in this case 4 case fan(ZALMAN Z3 PLUS) should put in one more fan ?(GREEN LINE)
My case now: https://gyazo.com/b829f7111a128fe945a2d6efcc41a360

 

[techgeek]

How are the temps of your HDD? This fan would obviously be an intake fan. Your present fan setup has negative air pressure which means that you are attempting to exhaust more air than you intake. I've always been a proponent of positive air pressure. However this is a touchy subject and others will tell you that negative air pressure is better. So if I'm reading this correctly, adding this fan should balance your air intake with exhaust (fan numbers, not necessarily CFM's). I'd say go for it if you think it will improve your temperatures and your system isn't already annoyingly loud.

If you do add this fan, I would clean up your cabling in your drive cage and in front of it as well. No point in adding a fan if there are a bunch of cables obstructing it's airflow.