The Corsair Obsidian 900D conforms to the E-ATX form factor and so can accommodate motherboards with form factors ATX, E-ATX, Micro-ATX, XL-ATX and Mini-ITX.
Its dimensions (LxWxH) are 640mm x 250mm x 680mm.
|Form Factor||E-ATX||Top Fans||2|
|Motherboard Form Factors||Top Fans Size||200mm|
|Material||Not sure||Side Fans||4|
|Color||Black||Side Fans Size||120mm|
|Expansion Slots||10||Rear Fans||1|
|5.25″ Drive Bays||4||Rear Fans Size||140mm|
|3.5″ Drive Bays||9||HDD Fans||3|
|2.5" Drive Bays||3||HDD Fans Size||120mm|
|Tool-less Rails||yes||Bottom Fans||1|
|Length||640mm||Bottom Fans Size||140mm|
|Width||250mm||IO Display Panel||yes|
|Height||680mm||Front USB 2.0 Slots||4|
|Maximum Graphics Card Length||450mm||Front USB 3.0 Slots||2|
|Front Fans Size||120mm||Audio IO||yes|
The Corsair Obsidian 900D has a the E-ATX form factor. Extended ATX is a slightly deeper version of the ATX standard which is designed to provide all the advantages of ATX but with slightly more room. Using the E-ATX standard, the case can house motherboards and power supplies with form factors ATX, E-ATX, Micro-ATX, XL-ATX and Mini-ITX. The dimensions of the case itself (LxWxH) are 640mm x 250mm x 680mm.
The Corsair Obsidian 900D has ten expansion slots, so there is plenty of room for extra components, which may be a deciding factor when planning on the longevity and build type of a PC system. The case has four 5.25" drive bays, which is enough to house an optical drive and a couple of hard drives, while still having space for plenty more HDDs with the nine 3.5" drive bays that are also available. You can even install an SSD or laptop-sized HDD using one of the three 2.5" drive bays. Installation of hard drives into these drive bays is made all the more easier by screwless rails that allow tool-less mounting.