Main Memory Configuration; Single-Channel Vs. Dual-Channel - HP Dx5150 - Compaq Business Desktop Configuration Manual

Main Memory Configuration

Single-channel vs. Dual-channel

The dx5150 business desktop includes four DIMM slots, organized in two independent memory
channels. A "dual channel" configuration might put identical DIMMs in the first slot of each channel,
for example, so that both channels operate simultaneously. This organization provides better memory
performance. The first slot of each memory channel is colored black. The second slot of each channel
is colored blue. Each pair of colored slots can either contain one DIMM (in the first slot), or a pair of
identical (in size and organization) DIMMs.
• In single-channel mode, the memory bus is 64 bits wide. The processor can often waste valuable
CPU cycles waiting for access to memory.
• In dual-channel mode, the memory bus is 128 bits wide, doubling the maximum memory
bandwidth. Memory performance can improve significantly.
Figure 1. Channels and Colors
Item Description
1 DIMM socket XMM1, Channel A
2 DIMM socket XMM2, Channel B
3 DIMM socket XMM3, Channel A
4 DIMM socket XMM4, Channel B
Socket Color
Black
Black
Blue
Blue
3