A Closer Look - Inside

Simply remove the glass panel on top to access the interior. Doing so will essentially allow you to put together the whole system so long as you do not use an ODD. The PC-O5S is actually quite elaborate in its internal layout, with many different parts coming together to make the most of the space within. You may, however, also remove the bottom panel (here put on display with the chassis in an upright position) to install an ODD. This panel is held in place by four small screws, which is not enough for such a big panel without any latches or other clips to hold it in place. The result of such a simple approach is a side panel that does not sit flush against the frame - an eye sore to someone who just spent over 300 USD on the chassis. Its steep price is also the reason we are rather picky in this review. Lastly, there is a large opening and dust filter right below the chassis' motherboard area. You may also install a 140 mm fan there to funnel some air toward the motherboard's backside, which would reduce its temperatures nicely.


The motherboard area sits right next to two 120 mm fans, while a ribbon cable of high quality allows the graphics card to be situated rather far away. The area is on the left and consist of four expansion slots, which would allow for a hard drive on the floor and a dual-slot GPU above the drive.


The ribbon cable is sleeved to protect it from sharp and pointy objects, which makes it a bit sturdier. Follow it and it will take you to a PCIe x16 slot all the way to the left, which you may move and align with any of the four expansion slots. This very elaborate approach is by no means necessary, but incredibly nifty to have. We will leave it as is for this review as the chassis offers many other locations for hard drives.


Starting with the floor, it may hold up two 2.5'' or 3.5" units, but the position toward the rear of the chassis is taken up by the expansion slot's cover. You could remove the cover if your intent were to install as many drives as possible. Three more 3.5" drives will fit into a classic cage next to the expansion slot. You may also remove the cage to install a long graphics card instead. This brings the total number of possible drives in this area of the chassis up to five.


The PC-O5S uses the SFX standard for its PSU bay. Given an interior bracket is used, you will have to route the power cable into the enclosure to connect it. The bracket had been pre-assembled wrongly out of the box, which I fixed during assembly. Lian Li will make sure your piece comes mounted to the chassis correctly - but it would not be an issue anyway as you have to remove it to attach the power supply. The aforementioned 120 mm fans on the side are protected by two black metal grills and are set to pull air out of the chassis. You may also use this area for a liquid-cooling setup with a 240 mm radiator for the CPU.


The ODD bay consists of a single piece of aluminum that has been bent into shape. Four mounting holes here allow you to place a 2.5'' drive there instead of an ODD. You will also find an additional bracket for two more hard drives. Its mixture of mounting holes allows for a 3.5'' and a 2.5" variant or two 2.5'' drives, which bumps the total number of hard drives you may put into the chassis up to seven if you use that expansion slot in an elevated position or eight if you manage to find a Mini-ITX board with eight SATA ports - should such a board even exist. This brings me to another point: considering the board's Mini-ITX format, there is very little reason for as many drives. I would have removed the HDD cage to move both mounting possibilities on the floor toward the front slightly, which would result in up to five hard drives without loosing that expansion slot and allows for really long GPUs; and removing a part would also reduce the price.

That said, all these possibilities for drives are also pretty cool if you intent to use an add-on card for more SATA ports.


A quick look at the cables within reveals nothing extraordinary. All the leads are sleeved black and come with the connector you would expect, so you should have no problem connecting these to a modern motherboard. I would have liked to see the ability to plug the USB 3.0 header into a 2.0 port, though.