Technical Product Specification

Table Of Contents
Intel
®
Server Board S5400SF TPS Functional Architecture
Revision 2.02
Intel order number: D92944-007
27
3.2.3.7 FBD Memory Thermal Management
The Intel
®
5400 MCH Chipset implements an adaptive throttling methodology to limit the number
of memory requests to the FBDIMMs. This methodology is comprised of the following:
Activation throttling: Consists of closed/open loop throttling of activates on the
FBDIMM.
- Closed Loop Thermal Activate Throttle Control when the temperature of the
FBDIMMs increases beyond a specified threshold.
- Open Loop Global Activate Control to limit requests when the number of activates
crosses an event threshold in a large time window.
Electrical Throttling: To prevent silent data corruption by limiting the number of
activates per rank in a small sliding window.
3.2.3.8 BIOS Support of Memory Subsystem
The BIOS is able to configure the memory controller dynamically in accordance with the
available FBDIMM population and the selected RAS (reliability, availability, serviceability) mode
of operation.
3.2.3.8.1 Memory sizing and Configuration
The BIOS supports various memory module sizes and configurations. These combinations of
sizes and configurations are valid only for FBDIMMs approved by Intel. The BIOS reads the
Serial Presence Detect (SPD) SEEPROMs on each installed memory module to determine the
size and timing characteristics of the installed memory modules (FBDIMMs). The memory-sizing
algorithm then determines the cumulative size of each row of FBDIMMs. The BIOS programs
the Memory Controller in the chipset accordingly, such that the range of memory accessible
from the processor is mapped into the correct FBDIMM or set of FBDIMMs.
3.2.3.8.2 POST Error Codes
The range {0xE0, 0xEF} of POST codes is used for memory errors in early POST. In late POST,
this range is used for reporting other system errors as follows:
If no memory is available, the system emits a POST Diagnostic LED code 0xE1 and
halts the system.
If the BIOS cannot electrically identify and thus communicate with the AMB on an
installed FBDIMM, the BIOS eventually times out and reports a POST Diagnostic LED
code 0xE4. This is usually indicative of hardware failure in the serial channel on which
the AMBs sit.
If a FBDIMM or a set of FBDIMMs on the same FBD memory channel (row) fails Intel
®
Interconnect BIST (Intel
®
IBIST), or Memory Link Training, the BIOS emits a POST
Diagnostic LED code 0xE6. If all of the memory fails Intel
®
IBIST, the system acts as if
no memory is available.
If the BIOS detects an FBDIMM with bad or corrupted SPD data, it emits a POST
Diagnostic LED code 0xEB and halts the system.
If a FBDIMM has no SPD information at all, the BIOS treats that FBDIMM slot as if no
FBDIMM is present on it at all. Therefore, if this is the only FBDIMM installed in the