Here’s what we are starting with: a completely assembled HD 4870 X2. To start, I removed the plastic heatsink shroud and fan assembly…
…which leaves you with this: the two bare heatsinks and the memory and PWM heatsink.
Here’s a nice shot of memory and PWM heatsink which is essentially a thick piece of aluminum with fins in appropriate areas.
Next you unscrew the backplate that covers the eight memory chips on the backside of the PCB, unveiling a rather boring piece of PCB.
Next up, unscrew the mounts for the main heatsinks and remove them and the front memory and PWM heatsink to reveal all the bits and pieces that make this card a beast.
Above is a reference PCB. I know the differences aren’t easily discernible but PaLiT has added a VGA outlet, rotated the external power connectors 90 degrees, and changed the PWM chokes. Otherwise, the reference and custom PCBs look quite similar.