Modes Of Operation; Single And Dual Channel Configuration Population Rules - Intel S7000FC4UR Technical Product Specification

BIOS Initialization
14.2.3

Modes of Operation

The BIOS configures the system memory into the best possible configuration after comparing
the current FBDIMM population with the desired memory configuration selected by the user in
BIOS Setup. Possible configurations are:
Dual-channel Mode (Maximum Performance Mode): The default setting providing the
highest system performance and increased FBD bandwidth. This requires each lock-
stepped pair of FBDIMMs on a branch to be identical. A lock-stepped FBDIMM pair is
defined as the FBDIMMs installed in identically numbered FBDIMM sockets on both
memory riser boards (channels) on a given Memory Branch.
Single-channel Mode: A failsafe mode when the installed memory configuration is
incompatible with dual-channel operation. In single-channel mode, only Branch 0,
Channel 0 is operational with all other FBDIMMs disabled automatically.
DIMM Sparing Mode: Only supported in a lock-stepped (dual-channel) configuration.
DIMM Sparing is the use of a lock-stepped FBDIMM rank on a memory branch to
provide a backup in case any other lock-stepped FBDIMM rank on the same branch
exceeds a user-selectable Memory ECC Correctable Error threshold in a fixed time
period. This failure prediction mechanism allows the system to automatically:
Copy the contents of a failing FBDIMM rank to a backup or spare FBDIMM rank
-
Disable the failing FBDIMM rank
-
These actions are completed before the FBDIMM rank begins to generate more serious
memory ECC uncorrectable errors that would bring down the system by corrupting
memory.
Memory Mirroring Mode: Memory Mirroring is a high availability mode providing a
redundant image of the system memory. This image allows the system to continue
operating if memory ECC uncorrectable errors would otherwise bring down the system in
another memory configuration.
See RAS Features for details about the DIMM Sparing and Memory Mirroring features.
14.2.4

Single and Dual Channel Configuration Population Rules

Memory must be populated beginning with Memory Riser Board A, Slot 1.
Memory riser boards must be populated beginning with DIMM Slot 1 and proceeding
with consecutively numbered slots.
Corresponding, identically-numbered FBDIMM sockets for both memory riser boards
(channels) on a branch must be populated with identical FBDIMMs in terms of timing,
technology, and size for the branch to operate in lock step (dual-channel) mode.
FBDIMMs installed in different socket positions (numbers) on a memory riser board do
not need to be identical for dual-channel operation.
Branch 0 is always given precedence over Branch 1 in determining the system memory
mode.
The BIOS uses FBDIMM in Slot 1 on both Memory Riser Board A and B (Branch 0) to
determine the memory mode.
The BIOS always selects the mode of operation that best matches the requirements of
Memory Riser Board A, DIMM Slot 1, such that it is always enabled and used for runtime
112
Intel® Server System S7000FC4UR
Revision 1.0