Specifications

The T420 supports memory speeds of 1600MT/s, 1333MT/s, 1066MT/s, and 800MT/s depending on
the DIMM types installed and the configuration. All memory on all processors and channels run at
the same speed and voltage. By default, the systems run at the highest speed for the channel with
the lowest DIMM voltage and speed. The operating speed of the memory is also determined by the
maximum speed supported by the processor, the speed settings in the BIOS, and the operating
voltage of the system.
Table 10 lists memory configuration and performance details for the T420 based on the population
of the number and type of DIMMs per memory channel.
DIMM
type
DIMM 0
DIMM 1
Number
of
DIMMs
Speed (MT/s)
800
1066
1333
1600
UDIMM
SR
1
∞
∞
∞
DR
1
∞
∞
∞
SR
SR
2
∞
∞
∞
SR
DR
2
∞
∞
∞
DR
DR
2
∞
∞
∞
RDIMM
SR
1
∞
∞
∞
∞
DR
1
∞
∞
∞
∞
QR
1
∞
∞
SR
SR
2
∞
∞
∞
∞
SR
DR
2
∞
∞
∞
DR
DR
2
∞
∞
∞
∞
QR
SR
2
∞
QR
DR
2
∞
QR
QR
2
∞
RAS features help keep the system online and operational without significant impact to performance,
and can decrease data loss and crashing due to errors. RAS aids in rapid, accurate diagnosis of faults
that require service. Table 11 describes the RAS features supported on the T420.
Feature
Description
Dense configuration
optimized profile
Increased memory reliability can be a result from this selectable platform profile
that adjusts parameters to reduce faults regarding refresh rates, speed,
temperature and voltage
Memory demand and
patrol scrubbing
Demand scrubbing is the ability to write corrected data back to the memory once
a correctable error is detected on a read transaction.