The old: Gateway's E-Series 4300 is an ATX desktop. This venerable design relies on a single chassis fan and, according to the company, locates components such as the processor (under the fan) more rearward and thus in a less ideal area for cooling. The drawback: Airflow is becoming more important as today's higher-speed chips can use more power and thus run hotter.

The new: The Gateway E-Series 6300 uses a BTX chassis, which locates fans on either end and places major components, including the processor (underneath the black box in the middle of the frame) in between. That creates a direct "wind tunnel" flow of air to keep the parts cooler. The machine's fans are also larger and rotate more slowly, cutting down on noise.

Location, location, location: A side-by-side comparison of the BTX desktop (on the left) and ATX shows key differences in how components are placed. The BTX eliminates the need for a fan on top of the processor, though the chassis can be slightly larger.