Chassis Plans ATXP-875P, Техническое описание

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ATXP-875P: Upgrading Chapter 3:Upgrading
Chassis Plans 41
Memory Configurations
The ATXP-875P 875P MCH component provides two features for enhancing memory throughput:
•
Dual Channel memory interface. The board has two memory channels, each with two DIMM sockets, as
shown in
Figure 3-1 .
•
Dynamic Addressing Mode. Dynamic mode minimizes overhead by reducing memory accesses.
Table 3-2 summarizes the characteristics of Dual and Single Channel configurations with and without the use of
Dynamic Mode.
Figure 3-1 Memory Channel Configuration
Table 3-2 Characteristics of Dual and Single Channel Configuration with and without Dynamic Mode
If either only channel A or only channel B is populated then the MCH is set to operate in single-channel mode. Data
will be accessed in chunks of 64 bits (8 B) from the memory channels. If both the channels are populated with
uneven memory (DIMMs), then the MCH defaults to virtual single-channel mode. The MCH behaves identically in
both single-channel and virtual single-channel modes. In dual-channel mode of operation the data accessed by the
MCH from the memory will be in chunks of 128 bits (16 B) from both the channels, hence the bandwidth in this
case will be double that of in SC mode.
Throughput Level Configuration Characteristics
Highest
Dual Channel with Dynamic Mode
All DIMMs matched
(Example configurations are shown in
Figure
3-2 )
Dual Channel without Dynamic Mode
• DIMMs matched from Channel A to
Channel B
• DIMMs not matched within channels
(Example configuration is shown in
Figure 3-
3 )
↑
Single Channel with Dynamic Mode
Single DIMM or DIMMs matched within a
channel
(Example configurations are shown in
Figure
3-4 )
Lowest
Single Channel without Dynamic Mode
DIMMs not matched
(Example configurations are shown in
Figure
3-5 )