A security arrangement (10) is adapted to improve heat dissipation from circuit board components (12, 14, 16, 18, 20) on a computer circuit board (22), where a plurality of the circuit components (12, 14, 16, 18, 20) are embedded in a security shield (5) and thermally connected to at least one heat exchanger device (24). The heat exchanger device (24) is located at a distance from the security shield (5), and at least a plurality of the circuit components (12, 14, 16, 18, 20) are thermally connected with said at least one heat exchanger device (24) via at least one heat dissipating lead (32, 33, 34) to enhance cooling of the circuit board components (12, 14, 16, 18, 20).