Intel Hyper-Threading Technology
Hyper-Threading (HT) Technology lets each core execute two computational threads simultaneously, which allows each four-core processor to simultaneously execute up to eight threads. As a result, HT Technology improves performance-per-watt by allowing ProLiant G6 servers to do more using the same or less power than the previous generation of ProLiant servers.
Intel Turbo Boost Technology
Turbo Boost gives an administrator the option to manually or automatically turn off individual cores and run the remaining cores faster than their nominal frequency, provided there is power and thermal headroom to do so. The administrator can determine the headroom using criteria such as the desired number of active cores, estimated power use, and maximum processor temperature.
DDR3 memory technology
DDR3, the third generation of DDR memory, delivers higher speeds, lower power consumption, and more effective heat dissipation than DDR1 and DDR2 memory. HP DDR3 dual in-line memory modules (DIMMs) include an integrated thermal sensor to prevent failures due to overheating and reduce power consumption when memory is idle. HP also provides an on-line memory configuration tool to simplify memory configuration.
ProLiant G6 servers based on the Intel Xeon 5500 series processor support DDR3-800, DDR3-1066, or DDR3-1333. DDR3 DIMMs provide the same reliability, availability, and serviceability as DDR2 DIMMs; however, DDR3 DIMMs have lower latency and twice the bandwidth. DDR3 DIMMs operate at 1.5V, compared to 1.8V for DDR2 DIMMs. This translates into more than 25% in power savings comparing the fastest DDR2 DIMM (DDR2-800) to the slowest DDR3 DIMM (DDR3-800). The power savings increase to almost 35% comparing the most commonly used DIMMs, DDR2-667, and DDR3- 1066.
HP DDR3 DIMM modules have an integrated thermal sensor that signals the chipset to throttle memory traffic to the DIMM if its temperature exceeds a programmable critical trip point. By using the data from these thermal sensors, ProLiant G6 servers can reduce fan speed when memory is idle, and thereby reduce power consumption. Some third-party DDR3 DIMMs may not include a thermal sensor. Therefore, the BIOS in ProLiant G6 servers checks for the presence of the DIMM thermal sensor during POST and displays a message if there is no thermal sensor.
It is important to note that there are two types of DDR3 DIMMs—registered (RDIMMs) and unbuffered (UDIMMs)—and they cannot be used together in a system. ProLiant G6 servers support up to three RDIMMs per channel or up to two UDIMMs per channel. RDIMMs have larger capacity (up to 16GB each) than UDIMMs (up to 2GB each). Higher-end ProLiant G6 servers support up to 18 DIMMs. In these servers, RDIMMs enable a total memory capacity of up to 192GB, compared to 24GB for UDIMMs. This makes RDIMMs the ideal choice for virtualization, while UDIMMs provide cost and power savings for less memory-intensive applications.
The memory channels can operate at up to 1333 MHz, but the actual speed depends on the number and type of DIMMs populating the slots. Using 95-W Intel Xeon 5500 series processors, ProLiant G6 servers support up to six dual-rank DDR3-1333 RDIMMs per processor (2 RDIMMs per channel) at 1333 MHz. The type of workload dictates the optimum number and type of DIMMs to use. For example, memory capacity may be of primary importance in virtualization environments, while memory channel speed may be more critical for high performance computing applications.
Because there are several memory options, HP simplifies memory selection by providing the on-line ProLiant Memory Configuration Tool (www.hp.com/go/ddr3memory-configurator), which takes users through the steps to configure server memory and provide an orderable parts list.