User Guide

Datasheet, Volume 1 of 2 23
Interfaces
address of the channel with the smaller capacity is reached. In this mode, the system
runs with one zone of dual-channel mode and one zone of single-channel mode,
simultaneously, across the whole memory array.
Note: Channels A and B can be mapped for physical channel 0 and 1 respectively or vice
versa. However, channel A size should be greater or equal to channel B size.
Dual-Channel Symmetric Mode (Interleaved Mode)
Dual-Channel Symmetric mode, also known as interleaved mode, provides maximum
performance on real world applications. Addresses are ping-ponged between the
channels after each cache line (64-byte boundary). If there are two requests, and the
second request is to an address on the opposite channel from the first, that request can
be sent before data from the first request has returned. If two consecutive cache lines
are requested, both may be retrieved simultaneously, since they are ensured to be on
opposite channels. Use Dual-Channel Symmetric mode when both Channel A and
Channel B DIMM connectors are populated in any order, with the total amount of
memory in each channel being the same.
When both channels are populated with the same memory capacity and the boundary
between the dual channel zone and the single channel zone is the top of memory, IMC
operates completely in Dual-Channel Symmetric mode.
Note: The DRAM device technology and width may vary from one channel to the other.
2.1.4 System Memory Frequency
In all modes, the frequency of system memory is the lowest frequency of all memory
modules placed in the system, as determined through the SPD registers on the
memory modules. The system memory controller supports up to two DIMM connectors
per channel. If DIMMs with different latency are populated across the channels, the
Figure 2-1. Intel
®
Flex Memory Technology Operations
CH BCH A
B B
C
B
B
C
Non interleaved
access
Dual channel
interleaved access
TOM
CH A and CH B can be configured to be physical channels 0 or 1
B – The largest physical memory amount of the smaller size memory module
C – The remaining physical memory amount of the larger size memory module