As it was with Nine Hundred, the power supply unit in the Three Hundred is located at the bottom of the chassis, which could cause some consternation with drive placement and cabling. PSUs with bottom mounted fans must be installed in an inverted position, and the Three Hundred is constructed to accept either orientation. We did have an issue with installing an older Vantec Stealth PSU, as the power switch didn't fit in neatly within the provided opening, but most other models should have no problems here. One must also check that their own PSU also has long enough cables to reach the top of the chassis, where the furthest most drive may be installed.
Both fans that come standard derive their power from 4-pin Molex connectors, rather than the 3-pin kind that plug directly into the motherboard, and have speed controls that hang nearby. The 120mm rear fan has speed/noise settings as follows: "High" runs at 2000 rpm, producing an airflow of 79 CFM at 30 dBA, "Medium" at 1600rpm with 56 CFM at 28dBA, and "Low" running at 1200 rpm and 39 CFM at 25 dBA. The 140mm fan mounted on top has slower speeds, but pushes more air and has quieter operation. Its High operation runs at 1500 rpm, 94.6 CFM, and 31.8 dBA, Medium at 1100 rpm, 66.8 CFM at 21.4 dBA, and Low at a mere 700 rpm, 47 CFM, and 19.8 dBA.
There are nine bays in all, three for external 5.25" drives, and six more for internally installed 3.5" drives. Whereas the Nine Hundred came with at least one 3.5" to 5.25" drive bay adapter, the Three Hundred doesn't come with one, so those looking to install a floppy drive or other smaller device must contact Antec for one for an extra $10. The drive cages are standard, screw-in types and we we're a little bit letdown by not finding any improvement in this area. We would have preferred to see some sort of toolless installation option; either rail driven or some either means. Even better would have been the inclusion of sound-dampening measures to limit the chattering of the hard drives. Second to the noise output of the numerous fans in today's chassis is the noise caused by the ever present movement of the hard drive, especially so when running Vista.
Cables dangle from the front panel into the main area, consisting of audio and USB headers, as well as the power, reset, and IDE usage LEDs. The backplane has tie-down points, good for anchoring cables and arranging them out of the way of needed airflow. A large opening towards the front also allows cables to run underneath the tray, further reducing cable clutter and bettering aesthetics, although without a windowed opening, no one will likely see the interior.