A server room can have a working AC unit and still overheat equipment — because cooling a room and cooling a rack are not the same problem. Most overheating issues come down to airflow being blocked or recirculated, not a lack of raw cooling capacity.
Virtually every rack server (and most rack switches) draws cool air in through the front and exhausts hot air out the back — a deliberate industry-wide standard, not a coincidence. This means a rack's physical orientation matters: if cold air can't reach the front of every unit, or hot exhaust air can recirculate back to the front, individual servers will run hot even in a cold room.
In a room with multiple racks, arrange them so all rack fronts face one aisle (the cold aisle, where AC output is directed) and all rack backs face the opposite aisle (the hot aisle, where hot exhaust collects and returns to the AC). This single layout decision — instead of racks facing randomly — is usually the single biggest airflow improvement available in a small server room, and costs nothing to implement.
If airflow and layout are correct and a specific server still runs hot, check that server's own internal fans and heatsinks — dust buildup on a refurbished or long-deployed unit is a common, easily fixed cause. Every server we supply is tested and cleaned before shipping, and we can advise on rack layout for a new deployment.
Planning a new server room or rack? Talk to our AMC & services team, or browse current tested inventory.