How can I ensure both case and RAM compatibility with my NH-D15 (G2)?

Using the NH-D15 and NH-D15 G2 coolers with RAM modules taller than 32mm:

• Option 1 - Moving the front fan up by a few millimetres 
  This will increase the total cooler height!
  If you are using RAM modules with a height of e.g. 35mm (3mm taller than 32mm), you need to move the fan up by 3mm, which increases the cooler height to 171mm (168mm + 3mm).
• Option 2 - Installing a 120mm fan instead of the included fan
  Replacing the fan above the RAM modules with a smaller 120mm fan makes room for up to 52mm tall RAM modules at a total cooler height of 168mm.
  As a 120m fan, we would recommend the NF-A12x25 G2 PWM or the NF-F12 PWM.
• Option 3 - Removing the fan above the RAM modules
  This way, only the heatsink will overhang the RAM modules.
  The total cooler height in this setup is: 160mm (NH-D15) / 168mm (NH-D15 G2)
  And there is space below the heatsink for RAM modules with a height of up to: 66mm (NH-D15) / 54mm (NH-D15 G2)
  Using the NH-D15 or NH-D15 G2 with only one fan will, however, lead to a slightly decreased cooling performance.
  

An increase in the total cooler height matters, as it could potentially lead to compatibility issues with your case, i.e. the case might be too narrow so that the side panel can no longer be closed.