Dell Vostro 3667 Owner's Manual page 34

Key Specifications
The table below shows the specifications comparison between DDR3 vs. DDR4:
Table 4. DDR3 vs DDR4
Feature/Option
Chip Densities
Data rates
Voltage
Low voltage standard
Internal banks
Bank groups (BG)
VREF inputs
tCK — DLL Enabled
tCK — DLL Disabled
Read Latency
Write Latency
DQ Driver (ALT)
DQ Bus
RTT Values (in Ω)
RTT not allowed
ODT Modes
ODT Control
Multi-Purpose Register
DIMM Types
DIMM Pins
RAS
DDR4 Details
There are subtle differences between DDR3 and DDR4 memory modules, as listed below.
Key notch difference
34 Technology and components
DDR3
512 Mb-8 Gb
800 Mb/s-2133 Mb/s
1.5 V
Yes (DDR3L at 1.35V)
8
0
2 —DQs and CMD/ADDR
300 Mhz-800 Mhz
10MHz – 125MHz (optional)
AL+CL
AL+CWL
40&Omega
SSTL15
120,60,40,30,20
READ Bursts
Nominal, Dynamic
ODT Signaling Required
Four Registers – 1 Defined, 3
RFU
RDIMM, LRDIMM, UDIMM,
SODIMM
240 (R, LR, U); 204 (SODIMM)
ECC
DDR4
4 Gb-16 Gb
1600 Mb/s-3200 Mb/s
1.2 V
Anticipated at 1.05V
16
4
1 — CMD/ADDR
667Mhz-1.6Ghz
Undefined to 125MHz
AL+CL
AL+CWL
48&Omega
POD12
240,120,80,60,48,40,34
Disables during READ Bursts
Nominal, Dynamic,Park
ODT Signaling Not Required
Four Registers – 3 Defined, 1
RFU
RDIMM, LRDIMM, UDIMM,
SODIMM
288 (R, LR, U); 260 (SODIMM)
CRC, Parity, Addressability,
GDM
DDR 4 Advantages
Larger DIMM capacities
Migration to higher speed I/O
Reduced memory power
demand
Memory Power Reductions
Higher data rates
Faster burst accesses
VREFDQ Now Internal
Higher data rates
DLL-off now fully supported
Expanded values
Expanded values
Optimal for PtP Applications
Less I/O Noise and Power
Support for higher data rates
Ease of use
Add'l Control Mode; OTF Value
Change
Ease of ODT Control; Allows
Non-ODT Routing, PtP Apps
Provides Additional Specialty
Readout
More RAS features; improved
data integrity