This case has ten 5 ¼” bays, coming with a removable hard disk drive cage for four hard drives that takes  three of these 5 ¼” bays (the front 120-mm fan is attached to this cage). The case also comes with adaptors to convert any of the 5 ¼” bays into a 3 ½” bay for installing a hard disk drive or a floppy disk drive. The 5 ¼” bays use a screwless mechanism to hold 5 ¼” devices, the HDD cage and the adaptor, but you still need to use screws to fasten the hard disk drives to the cage or the floppy disk drive (or fifth hard disk drive) to the adaptor.

So there are several possible disk drive configurations for this case. The standard configuration will give you four internal 3 ½” bays for hard disk drives and seven 5 ¼” bays. If you use the adaptor to install a floppy disk drive or an additional hard disk drive then you will have six 5 ¼” bays.

If you remove the HDD cage you will have all ten 5 ¼” bays available, but this is an unrealistic scenario, as all computers need at least one hard disk drive. If you really need a lot of 5 ¼” bays, then you can remove the HDD cage and install just one hard drive using the adaptor, allowing nine 5 ¼” bays to be available (the problem here is that this case comes only with eight screwless mechanisms for 5 ¼” devices, so the ninth device would need to be manually screwed).

The big question is: who needs that many 5 ¼” bays? We think that Cosmos S would be a far better product if it included a second HDD cage. This would expand the number of internal 3 ½” bays for hard disk drives to eight (or nine, if you use the extra adaptor), giving you four (or three, if the adaptor is used) 5 ¼” bays, which is more than enough even for a hardcore user.

Maybe Cooler Master did this thinking of users willing to install one of their water-cooling systems that use 5 ¼” bays. In any circumstance, these users could simply remove the extra cage if they needed more 5 ¼” bays and, at the same time, provide more internal 3 ½” bays for the users that need to install more hard disk drives.

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Figure 18: Hard disk drive cage.

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Figure 19: Hard disk drive cage outside the case.

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Figure 20: Hard disk drive cage outside the case.

To remove the hard disk drive cage you will need to remove four screws, two at each side of the cage. 

The hard disk drive cage is attached to the case using one aluminum plate at each side of the cage and the cage has four rubber rings to absorb the natural vibration produced by the hard disk drives (as they use motors that are spinning all the time). The problem is that each hard disk drive is attached to the cage without any rubber ring, a feature present on some cases that are cheaper than Cosmos S. We’d like to see this feature on Cosmos S, which is a very expensive case. Another problem with this case is that it isn’t really “tool less” as Cooler Master claims; you still need to use screws to fasten the hard disk drives to the cage. The screwless mechanisms are only used with 5 ¼” devices and also to hold the hard disk drive cage to the case.

You can not only remove the hard disk drive cage from the case to facilitate the installation of hard disk drives, but you can also reinstall it anywhere you want. It comes installed on the lower three 5 ¼” bays, but on Figure 21 we moved it to the middle three 5 ¼” bays.

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Figure 21: Hard disk drive cage on a different position.