The black abyss
The mechanism used to open the side panel of a case is one of those areas where I've seen more creativity lately. Compared to traditional thumbscrews, the 800D's push buttons are much quicker and more convenient to use. When fully depressed, the side panel's top edge pops off with a satisfying ca-chunk. The panel can then be lifted away with ease.
The first thought I had when I saw the interior of the 800D in person was much akin to Neo's infamous 'whoa'. If black is your absence of color of choice, you'll likely have a similar reaction when you open up the Obsidian. The fan blades, tool-less optical drive mounts, and individual rivets and motherboard standoffs all match the exterior color. I wouldn't normally make such a big deal over a seemingly minor aesthetic quality, but this sort of attention to detail is rare in the enclosure industry. Cases always seem to have at least one part, whether it's a bracket here or a screw there, that doesn't quite match everything else. Corsair's done an excellent job of blacking out everything inside and out of the 800D.
Now, there's more to be excited about in the interior than just the way it looks. Case makers are increasingly punching holes in motherboard trays to allow for cleaner cable routing, and the 800D takes this to the extreme with 13 rubber-lined holes. Slots next to the drive bays in both the top and bottom portions of the case bring the total number of openings to 15, which is more than I've seen in any other enclosure.
A couple of holes also perforate the panel separating the top and bottom zones of the case to allow a water-cooling radiator or pump to reside in the lower section.
Much like other premium cases, the 800D separates its internals into two zones, with the power supply and a couple of standard hard drive bays living in the lower compartment. A 140-mm fan mounted to the underside of the zone divider draws air into the case through the bottom-panel intake vents and channels it up into the main compartment.
The 800D's third and final fan is another 140-mm model tucked behind a shroud attached to the hot-swap drive bays. This shroud's design directs air from the bottom of the case across the hard drives and then behind the motherboard tray, where it eventually makes its way out through the exhaust vents at the rear. With two fans drawing air in and only one active exhaust, the main chamber maintains a net positive air pressure, which helps to keep dust from making its way into the case through unfiltered vents. Excess warm air can easily makes its way out through the Obsidian's generous top-panel venting thanks to the miracle of convection.
There are two more hard drive bays in the bottom portion, but they don't include hot-swap caddies, and you'll have to add your own 120-mm fan to give them dedicated cooling. Corsair includes a fan shroud for the 120-mm mount to direct airflow over the hard drives.
After taking the right side panel off, the 15 cable routing holes are even easier to see. And now, we can also see where Corsair intends for all your extra cabling to go. The wiring for the port cluster and front panel is neatly bundled and long enough to reach the bottom of this side of the case before popping through to the other side. If you've ever been frustrated by having to remove your motherboard to install a CPU cooler with a custom back plate, you'll especially appreciate the removable panel just behind the socket area of the motherboard tray. Pop it out, and you have very good access for pretty much all modern sockets.