Dell OptiPlex 7460, Руководство по обслуживанию

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Feature/Option DDR3 DDR4 DDR 4 Advantages
DQ Bus SSTL15 POD12 Less I/O Noise and Power
RTT Values (in &Omega) 120,60,40,30,20 240,120,80,60,48,40,34 Support for higher data rates
RTT not allowed READ Bursts Disables during READ Bursts Ease of use
ODT Modes Nominal, Dynamic Nominal, Dynamic,Park Add’l Control Mode; OTF Value
Change
ODT Control ODT Signaling Required ODT Signaling Not Required Ease of ODT Control; Allows
Non-ODT Routing, PtP Apps
Multi-Purpose Register Four Registers – 1 Defined, 3
RFU Four Registers – 3 Defined, 1
RFU Provides Additional Specialty
Readout
DIMM Types RDIMM, LRDIMM, UDIMM,
SODIMM RDIMM, LRDIMM, UDIMM,
SODIMM
DIMM Pins 240 (R, LR, U); 204 (SODIMM) 288 (R, LR, U); 260 (SODIMM)
RAS ECC CRC, Parity, Addressability, GDM More RAS features; improved
data integrity
DDR4 Details
There are subtle differences between DDR3 and DDR4 memory modules, as listed below.
Key notch differenc e
The key notch on a DDR4 module is in a different location from the key notch on a DDR3 module. Both notches are on the insertion edge,
but the notch location on the DDR4 is slightly different, to prevent the module from being installed into an incompatible board or platform.
Figure 1. Notch difference
Increased thickness
DDR4 modules are slightly thicker than DDR3, to accommodate more signal layers.
Figure 2. Thickness difference
Curved edge
Technology and components 9