I would suggest variant of the cooling system. 
Use as the entire top cover of the case (completely instead of the top acrylic plate) a metal plate with an adapter, in the form of a metal cube, to contact the processor. You can use two configuration options.
- Without fan (for operation of the system with medium loads or at low ambient temperature).
2 . With additional fan on the top side of the cover (for maximum load or high ambient temperature).