The motherboard is fairly tough, but it doees show signs of strain when I move it with all the blocks installed.
I'm going to reinforce the board before installing it just be be safe.
The motherboard and RAM blocks are copper and nickel, the CPU and GPU blocks are copper and stainless steel.
Using copper and aluminum in the same loop will cause a galvanic reaction, in the form of corrosion and that can cause leaks and blockages. However stainless steel, nickel, and nickelized-copper have similar galvanic properties making them safe to combine.