Datasheet

Interfaces
Intel
®
Xeon
®
Processor C5500/C3500 Series
Datasheet, Volume 1 February 2010
44 Order Number: 323103-001
2.1.3.7.3 Intel
®
Flex Memory Technology Mode
This mode combines the advantages of the Dual/Triple-Channel Symmetric
(Interleaved) and Dual/Triple-Channel Asymmetric Modes. Memory is divided into a
symmetric and a asymmetric zone. The symmetric zone starts at the lowest address in
each channel and is contiguous until the asymmetric zone begins or until the top
address of the channel with the smaller capacity is reached. In this mode, the system
runs at one zone of dual/triple-channel mode and one zone of single-channel mode,
simultaneously, across the whole memory array.
This mode is used when Intel
®
Flex Memory Technology is enabled and both Channel A,
Channel B, and Channel C DIMM connectors are populated in any order with the total
amount of memory in each channel being different.
Figure 5. Dual-Channel Symmetric (Interleaved) and Dual-Channel Asymmetric Modes
CH. B
CH. A
CH. B
CH. A
CH. B
CH. A
Channel selector
controlled by DCC[10:9]
CL
0
Top of
Memory
CL
0
CH. B
CH. A
CH.A-top
DRB
Dual Channel Interleaved
(memory sizes must match)
Dual Channel Asymmetric
(memory sizes can differ)
Top of
Memory
Figure 6. Intel
®
Flex Memory Technology Operation
CH BCH A
CH BCH A
B B
C
BB
C
B
B
C
Non interleaved
access
Dual channel
interleaved access
TOM
B – The largest physical memory amount of the smaller size memory module
C – The remaining physical memory amount of the larger size memory module