The next step is to prepare the heat sink/fan (HSF) unit. Intel supplies an appropriate HSF with retail-boxed processors, shown in Figure 9. (We named this one Godzilla, for obvious reasons.) If you're using the bundled retail heat sink, make sure to strip off the plastic that covers the copper contact surface. Robert seldom reads instructions, so he almost missed the plastic, which is more evident in the photograph than in real life. We shudder to think what might have happened had we installed the HSF without removing the plastic. Our expensive new Pentium 4 560 would have been covered in melted plastic.
Fortunately, Barbara reads instructions.
Figure 9. Preparing the heat sink/fan unit
Unlike older sockets, which use cammed clamps to force the HSF tightly into contact with the processor, Socket 775 uses simple fastener caps to secure the HSF to the motherboard, placing very little pressure or stress on the socket or the processor itself. To install the HSF, place it gently in position, with its four fastener caps aligned with the corresponding holes in the motherboard. The HSF is symmetric, and it doesn't matter which fastener cap mates with which hole. Once you have all four fastener caps aligned, press down gently on each one until it clicks into place, as shown in Figure 10.
Figure 10. Securing the heat sink/fan unit
Once the HSF is secured, connect the fan power lead to the four-pin fan power header next to the processor socket, as shown in Figure 11. Be very careful about routing the wires. Unlike most HSF units, which enclose the fan blades in a cage, the stock Intel HSF uses exposed fan blades, visible in Figure 10. Intel recommends running the four fan wires down through the body of the heat sink and securing the excess wire length to ensure that the wires can't foul the exposed fan blades.
Figure 11. Connecting the CPU fan
With the processor installed, the next step is to install the memory modules. We're installing two 512MB DDR2 DIMMs rather than one 1GB DIMM because the D925XCV supports dual-channel memory operation, which greatly increases memory throughput. A DDR2 DIMM closely resembles a standard DDR DIMM and is installed the same way. The only visible difference is that most DDR DIMMs have 184 pins, while DDR2 DIMMs have 240 pins.
The D925XCV provides four memory slots, two for Channel A labeled 0 and 1, and two for Channel B, also labeled 0 and 1. To enable dual-channel memory operation, we need to install one DIMM for each channel. Slot 0 for each channel uses a blue socket, and Slot 1 a black socket. As a matter of good practice, we installed our DIMMs in Slot 0 of each channel, leaving the black slots unoccupied and available for later expansion.
Figure 12. Installing a memory module