Dell Vostro 5581 Service Manual - Page 8

2 Technology and components NOTE: Instructions provided in this section are applicable on computers shipped with Windows 10 operating system. Windows 10 is factory-installed with this computer. Topics: • DDR4 • USB features • USB Type-C • Intel Optane memory • Intel UHD Graphics 620 • Nvidia GeForce MX130 equivalent 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 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. DDR4 Details There are subtle differences between DDR3 and DDR4 memory modules, as listed below. Key notch difference 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. 8 Technology and components