Processor/Memory Subsystem

3.3.1 Memory Loading/Upgrading

Table 3-2 shows suggested memory configurations for these systems.

CAUTION: Always power down the system and disconnect the power cord from the AC outlet before adding or replacing memory modules. Changing memory modules while the unit is plugged into an active AC outlet could result in equipment damage.

✎Table 3-2 does not list all possible configurations.

Table 3-2.

Memory Socket Loading

 

 

 

 

Channel A

Channel B

 

 

Socket

Socket

Socket

Socket

 

 

XMM 1

XMM 3

XMM 2

XMM 4

 

Total

 

 

 

 

 

none

none

none

512 MB

512 MB (single channel loading)

none

512 MB

none

512 MB

1

GB (dual-channel loading)

none

none

none

1 GB

1

GB (single chanel loading)

none

1 GB

none

1 GB

2

GB (dual-channel loading)

1 GB

1 GB

1 GB

1 GB

4

GB (dual-channel loading)

none

2 GB

none

2 GB

4

GB (dual-channel loading)

2 GB

2 GB

2 GB

2 GB

8

GB (dual-channel loading)

✎If only one DIMM is installed, it MUST be installed in socket 4.

HP recommends using dual-channel loading (symmetrical, same-capacity, same-speed modules across both channels) to achieve the best performance. The system automatically selects single- or dual-channel operation depending on how DIMMs are installed. For dual-channel operation, the loading priority is to populate socket XMM4 before XMM2 for channel B, and socket XMM3 before XMM1 for channel A.

✎Memory amounts over 3 GB may not be fully accessible with 32-bit operating systems due to system resource requirements. Addressing memory above 4 GB requires a 64-bit operating system.

3.3.2Memory Mapping and Pre-allocation

Figure 3-2 shows the system memory map. The RS780C North Bridge pre-allocates a portion of system memory for video use (refer to chapter 6). Pre-allocated memory is not available to the operating system. The amount of system memory reported by the OS will be the total amount installed less the pre-allocated amount.

 

3-4

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Technical Reference Guide