A cooling device including a split-core with a plurality of twin fins connected with a plurality of grooves on the split-core is disclosed. Each twin fin includes a root and a pair of vanes extending from the root. Each root is connected with one of the grooves to mount the twin fins to the split-core. A heat spreader is in contact with a top portion of the vanes and a heat pipe is connected with the heat spreader and the split-core. A heat concentration in the split-core is dissipated by a thermal path through the heat pipes to the heat spreader and into the vanes and also by a path upward into the split-core and into the vanes via the roots of the twin fins.