[Jacques]

They essentially look like two black heatsinks located closest to the board handle side. They attach via 2x each connectors to the gfx board. The connectors, if the solder is very old, have been known to pull away from the board. So beware if you clean / take them apart, best to leave them in-situ and use compressed air.

As always with Octanes, don't touch the compression connectors! 

See below links...