UPDATED.
If some image doesn't load, just refresh the page. Dropbox isn't too reliable unfortunately. I chose it as a medium over forum's upload mechanism only because the latter seems to compress images on its own, which I do not want.
Two master shots:
And three detail shots:
What was done in Houdini: Some modelling of base shapes (blades of both fans and all tubular shapes of the CPU cooler - some of which are not visible on this particular shot) and instancing of similar meshes; RBD simulation for realistic placement of all those nuts and bolts; rendering (Mantra); postproduction. Other software used: Nvil - subdivision modelling of all objects. 3D-Coat 4.5 BETA - UVs and texturing of all objects (but the floor). Bitmap2Material 3 - generating PBR textures of the wooden floor. Photoshop - tweaking displacement map of the floor (painting the spacing between the boards); stencils for texturing in 3D-Coat; post.
Took over 7 hours (edit: per shot) to render on a 3930K... Mostly because of those blasted semi-transparent motherboard rivets...
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Old, flat image can be accessed here: https://www.dropbox.com/s/vjbje6vcz2o8k4r/nuts_and_bolts_cam1_final.jpg?dl=1