Technical Product Specification

Table Of Contents
Intel
®
Server Board S5400SF TPS Server Management
Revision 2.02
Intel order number: D92944-007
61
Figure 14. Memory Throttle Settings Inputs
The following sections describe the functionality of each platform control mechanism:
4.5.2 FBDIMM Closed Loop Thermal Throttling (CLTT)
Closed Loop Memory throttling (CLTT) is a feature of the Intel
chipset to prevent FBDIMM
memory from overheating. This is a temperature based throttling feature. If the temperature of
the installed FBDIMMs approaches their thermal limit, the system BIOS initiates memory
throttling. This manages memory performance by limiting bandwidth to the DIMMs, therefore
capping the power consumption and preventing the DIMMs from overheating. By default, the
BIOS configures the system to support CLTT if it detects that there are functional AMB thermal
sensors present on all installed DIMMs. In the CLTT mode, the system fans run slower to meet
the acoustic limits for the given platform but this mode also allows the fans to ramp up as
needed to maintain the parts within temperature specifications under high stress levels.
In a similar way to OLTT, the system BIOS utilizes a Memory Reference Code (MRC) throttling
algorithm to maximize memory bandwidth for a given configuration. The MRC code relies on
Serial Presence Detect (SPD) data read from the installed DIMMs. Closed Loop Thermal
Throttling is autonomous and internal to the MCH hardware and the throttling algorithm always
throttles the minimum amount required to prevent the part from overheating.
Power Property
Heat Spreader
Type
AMB Thermal
Limit
DRAM Type
DRAM Thermal
Limit
FBDIMM Inputs
(SPD bytes)
Trise
Altitude
Pitch
Fan Flow
V
elocit
y
System Level Inputs
BIOS Setup & FRUSDR
+
BIOS MRC
Memory Throttle
Settings
System
Ambient