Dell OptiPlex 5260, Service Manual

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Technology and components
This chapter details the technology and components available in the system.
Topics:
• DDR4
• USB features
• HDMI
DDR4
DDR4 (double data rate fourth generation) memory is a higher-speed successor to the DDR2 and DDR3 technologies and allows up to 512
GB in capacity, compared to the DDR3's maximum capacity of 128 GB per DIMM. DDR4 synchronous dynamic random-access memory is
keyed differently from both SDRAM and DDR to prevent the user from installing the wrong type of memory into the system.
DDR4 needs 20 percent less or just 1.2 volts, compared to DDR3 which requires 1.5 volts of electrical power to operate. DDR4 also supports
a new, deep power-down mode that allows the host device to go into standby without needing to refresh its memory. Deep power-down
mode is expected to reduce standby power consumption by 40 to 50 percent.
Key Specifications
The following table lists the specifications' comparison between DDR3 and DDR4:
Table 1. DDR3 vs DDR4
Feature/Option DDR3 DDR4 DDR 4 Advantages
Chip Densities 512 Mb-8 Gb 4 Gb-16 Gb Larger DIMM capacities
Data rates 800 Mb/s-2133 Mb/s 1600 Mb/s-3200 Mb/s Migration to higher speed I/O
Voltage 1.5 V 1.2 V Reduced memory power
demand
Low voltage standard Yes (DDR3L at 1.35V) Anticipated at 1.05V Memory Power Reductions
Internal banks 8 16 Higher data rates
Bank groups (BG) 0 4 Faster burst accesses
VREF inputs 2 —DQs and CMD/ADDR 1 — CMD/ADDR VREFDQ Now Internal
tCK — DLL Enabled 300 Mhz-800 Mhz 667Mhz-1.6Ghz Higher data rates
tCK — DLL Disabled 10MHz – 125MHz (optional) Undefined to 125MHz DLL-off now fully supported
Read Latency AL+CL AL+CL Expanded values
Write Latency AL+CWL AL+CWL Expanded values
DQ Driver (ALT) 40&Omega 48&Omega Optimal for PtP Applications
DQ Bus SSTL15 POD12 Less I/O Noise and Power
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8 Technology and components