Intel
®
Core
TM
i7-660UE, i7-620LE/UE, i7-610E, i5-520E, i3-330E and Intel
®
Celeron
®
Processor P4505, U3405 Series
August 2010
Datasheet Addendum
Document Number: 323178-003
19
Interfaces
interfering with the current request allowing for concurrent issuing of requests. This
allows for optimized bandwidth and reduced latency while maintaining appropriate
command spacing to meet system memory protocol.
2.1.5.2
Command Overlap
Command Overlap allows the insertion of the DRAM commands between the Activate,
Precharge, and Read/Write commands normally used, as long as the inserted
commands do not affect the currently executing command. Multiple commands can be
issued in an overlapping manner, increasing the efficiency of system memory protocol.
2.1.5.3
Out-of-Order Scheduling
While leveraging the Just-in-Time Scheduling and Command Overlap enhancements,
the IMC continuously monitors pending requests to system memory for the best use of
bandwidth and reduction of latency. If there are multiple requests to the same open
page, these requests would be launched in a back to back manner to make optimum
use of the open memory page. This ability to reorder requests on the fly allows the IMC
to further reduce latency and increase bandwidth efficiency.
2.1.6
DRAM Clock Generation
Two differential clock pairs for every supported DIMM. There are total of four clock pairs
driven directly by the processor to two DIMMs.
2.1.7
DDR3 On-Die Termination
On-Die Termination (ODT) is a feature that allows a DRAM device to turn on/off internal
termination resistance for each DQ, DQS/DQS#, and DM signal via the ODT control pin.
The ODT feature improves signal integrity of the memory channel by allowing the
DRAM controller to independently turn on or off the termination resistance for any or all
DRAM devices themselves instead of on the motherboard.
The IMC drives out the required ODT signals, based on the memory configuration and
which rank is being written to or read from, to the DRAM devices on a targeted DIMM
module rank to enable or disable their termination resistance.
2.2
PCI Express* Interface
This section describes the PCI Express* interface capabilities of the processor. See the
PCI Express Base Specification for further details on PCI Express.
The processor has two options for PCI Express controllers available:
• 1 x16 PCI Express Port
or
• 2 x8 PCI Express Ports
— Enabled with CFG[0] strapping, see
2.2.1
PCI Express* Configuration Mechanism
The PCI Express* link is mapped through a PCI-to-PCI bridge structure.