Fractal design chose to go with two 140 mm fans in the bottom thus limiting the slots to two.
Fractal design r5 fan configuration.
For pc on the pc a gamefaqs message board topic titled best fan setup for fractal design define r5.
As you may have guessed from the title the case i got is the fractal design define r5.
The case sports two high quality and low noise fans 140mm already mounted one in the front and one in the back.
If there were three 5 25 slots this design would allow you to put a 120 mm or 140 mm intake fan there.
I read somewhere that they are sufficient for people who don t overclock.
The interior of the define r5 blackout is roomy and supports a variety of large radiators.
The define r5 case reaches the highest level of silent computing through strategically placed dense sound dampening material moduvent fan vent covers and finely tuned dynamic series fans.
The included 140mm fans spin at a maximum of 1000rpm and they are so quiet that even at maximum speed they are still silent.
Fractal design has included a built in three speed fan controller in the front panel which supports 5v 7v and 12v.
The door can be easily swapped to open from either side of the case.
Behind the door is an easily removable dust filter a single fractal design dynamic gp14 140 mm fan and two 5 25 bays.