For the Sonata Plus case, temperatures were monitored with the case's internal Antec 120mm Tricool exhaust fan set at both Low and High speeds.
All areas and components installed in the case are cooler at idle and load situations when the fan is set to High speed versus Low speed.
One area of special note is the Bottom PCI Slot area. This area is usual location in a case with stagnant airflow. Setting the case fan to high speed helps to circulate the air in this area, as we can see with the big drop in temperature. The difference in Load temperature for this section is 9 degrees celcius lower going from Low to High speed! For users running in a Crossfire or SLI configuration, running the case fan at High would help quite a bit in keeping temperatures low.
The Sonata Plus is a quiet case. It is whisper quiet when the exhaust fan is set to low, so if you put your computer on the floor, you should not be able to hear it. This level of quietness is achieved in a few ways. Noise in a computer is normally generated from mechanical parts. The Antec Tricool fan pre-installed in the case is barely audible at Low speed. Hard drive noise is cut down with the use of rubber grommits to absorb vibration. The sides and top of the case is lined with polycarbonate panels to help dampen noise.
With the Antec Tricool fan set to Medium, cooling performance is improved, and noise is still barely audible. With fan speed at High, the fan speed is more noticeable, but is low pitch. Most users should find the Sonata Plus case to be quiet enough for their needs. As well, most users should be able to run the case fan at Low speed and have more than sufficient cooling performance for their components. As a tip, if more cooling performance is needed and noise is a big issue, an extra 92mm fan (with a quiet noise rating) or two can be mounted in the case.