Disclosed are a method for preparing a high performance BGA board containing a plurality of printed circuit boards in which a conductor circuit, a bonding pad electrically connected to a semiconductor chip, and an inner hole for mounting a semiconductor chip are formed, by primary- and secondary-laminating a plurality of boards. The case includes a fixing portion fixing the ring member, and a fitting portion fitting on the ring member. To the extent that this early culling reduces the number of vertices for which the full set of attributes is computed or reduces the number of primitives or vertices delivered to downstream units, throughput of the processor is increased. The DCDC convertor dynamically adjusts an output voltage according to the efficiency controlling signals.