@mntmn Is this just a slab of copper without the fins? What made this simplification desirable? Is the new version now more heavy than the old? The fins were likely not very useful when pressed against the bottom acrylic. I always thought that if they are fins, then they should be pointing into the direction of the motherboard as there is probably more air convection happening. Do you have already tried out what the temperature difference is with this new heatsink?
@mntmn @josch Oh and another thought. Have you considered trying this same design as aluminum? If it works, that might be even less expensive than copper.