A Closer Look - The Big Chassis
Simply unscrew the thumbscrews to access the chassis' interior. The screws are pinned to the chassis, so you can't misplace them, and the interior of the HAF Stacker is, to go with the rest of the design, all-black. The layout is actually quite traditional, with the hard-drive bays in the front and the rest of the system in the back. Turning the chassis around, you will find numerous grommet-covered holes, including a large opening under the CPU area of the motherboard, for easy cable routing.
There is only around 20 mm of room between the motherboard tray and the side panel. While cable routing should still be possible, you will really have to squeeze things you will really have to squeeze the side panel on once the system has been assembled. There is also a spot to install a 2.5" SSD onto the back. A simple but functional implementation, it requires you to sink screws into the side of the drive.
The HAF Stacker ships with six hard-drive bays, which come grouped into two cages. You have to pull the front cover off to remove them, which reveals two 120 mm fan placement possibilities. You can pull the fans out once the screws are gone to clear the entire front of any obstacles, which allows for another radiator of up to 240 mm to be placed there.
Once the hard-drive cages are removed, you may disassemble them to place them into the smaller chassis, which allows you to use the smaller enclosure for a secondary system, your water-cooling loop, or a bunch of hard drives.
Each 5.25" drive bay comes with the plastic locks to hold its drive in place. We have come across these in the HAF XM already and know that they work, but you may still want to sink a single screw into your ODD to pin it down properly.
Everything in the rear of the larger chassis is quite traditional. The PSU bay in the bottom features an air vent with a dust filter, so you may install your PUS with the fan facing downward. Above that are the 8 + 1 motherboard-expansion slots. Each expansion slot comes with a cover that is held in place by a thumbscrew. The aforementioned 140 mm exhaust fan which pushes hot air out the back of the case can be found at the very top.
There to easily route cables into the smaller chassis on top or vice versa, numerous holes have been put into the ceiling of the large chassis. The underside comes with holes as well, but they have been configured differently - tipping the larger HAF Stacker chassis on its side allows you to take a closer look at those holes and the PSU bay's removable dust filter.
Every cables is sleeved black, and I did not find any leads for a reset button or HDD activity LED. All the I/O cables are also of the default variety, so you should easily be able to connect everything to a modern motherboard.