HP ProLiant G7 c-Class server blades with Intel® Xeon® processors

HP processor heat sink

The processor heat sinks in ProLiant server blades are smaller than those of rack-mount servers to

allow more space on the server blades for DIMM slots and hard drives. The server blade heat sinks

have vapor chamber bases, thinner fins, and tighter fin pitch than previous designs to achieve the

largest possible heat transfer surface in the smallest possible package (Figure 4).

Figure 4. Processor heat sink using fully ducted design (left) and traditional heat sink used in a 1U rack-mount

server (right)

Top view

Side view

Memory technologies

DDR3, the third generation of DDR memory, delivers higher speeds, lower power consumption, and

more effective heat dissipation than DDR1 and DDR2 memory. It is an ideal memory solution for

bandwidth-hungry systems equipped with multi-core processors. Depending on the memory

configuration and processor model, the memory may run at 1333, 1066, or 800 megatransfers per

second (MT/s).

DDR3 operates at 1.5 V (standard) and at 1.35 V (low voltage), which reduces both

power consumption and heat generation. DDR3 DIMMs have 240 pins, the same number and size as

DDR2. However, they are electrically incompatible and have different key notch locations.

DDR3 memory is available in two forms: Unbuffered (UDIMM) and Registered (RDIMMs). Both

UDIMMs and RDIMMs support error correcting code (ECC). Administrators can use either RDIMMs or

UDIMMs, but RDIMM and UDIMM memory cannot be mixed within a single server. When choosing

memory configurations using DDR3 memory, the following guidelines are useful:

 UDIMM configurations are limited to a maximum of two UDIMMs per memory channel because the

memory controller must drive the address and command signals to each DRAM chip on a channel.

This results in a 48-GB maximum configuration when using 4GB UDIMMs. Because they require

fewer components, UDIMMs are typically less expensive than RDIMMs.

 RDIMM configurations can provide larger memory capacity because the memory controller only

drives the address and command signals to a single register chip, thereby reducing the electrical

load on the memory controller. Users requiring large memory footprints can install up to two 16-GB

quad-ranked RDIMMs per channel, for a total of 192GB.

For additional information about HP server memory technology, go to the HP server memory site:

http://h18004.www1.hp.com/products/servers/options/memory-description.html.