Technology implementation in HP ProLiant G7 servers

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AMD Opteron 6100 series processors have a three-level cache hierarchy, including a dedicated
512KB L2 cache per core and up to 6MB shared L3 cache per die. Each die also has a dual-channel
memory controller that can support up to three DDR3 DIMMs per channel at 1333 MT/s.
The AMD Opteron 6100 series processors include the following:
HyperTransport (HT) Assist helps increase performance of 4P and 8P ProLiant servers. It maintains
data correctness (coherence) between the processors and minimizes inter-processor communication
traffic on the HyperTransport links. Each die has four 6.4-GHz HyperTransport 3.0 links.
AMD Smart Fetch lets cores enter a "halt" state during idle processing times, so they use less
power. The processor moves data from the L1 and L2 caches to the shared L3 cache before
entering the halt state, so that the active core can retrieve the contents of the idle cores.
Enhanced AMD PowerNow! reduces power requirements and heat by lowering the clock speed
and voltage when the processor is idle. It supports up to five power states and reduces power
consumption at idle by up to 75 percent.
AMD-V™ with Rapid Virtualization Indexing, or nested paging, reduces the overhead associated
with software virtualization.
AMD Opteron 6100 series processors include 65W, 80-W and 105-W versions. To see the
processor specifications, go to http://products.amd.com/en-
us/OpteronCPUResult.aspx?f1=AMD+Opteron%e2%84%a2+6100+Series+Processor .
Memory technologies
ProLiant G7 servers support DDR3 memory. DDR3 has several key enhancements including an 8-bit
prefetch buffer for storing data before the processor requests it. DDR2, by comparison, has a 4-bit
buffer.
DDR3 DIMMs
ProLiant G7 servers support DDR3-1333, DDR3-1066, or DDR3-800 DIMMs. Higher speed DIMMs
can operate at lower data rates. For example, DDR3-1333 DIMMs can operate at data rates of
1333, 1066, and 800 MT/s. The corresponding clock speeds are 667 MHz, 533 MHz, and 400
MHz.
There are two types of DDR3 DIMMs—registered (RDIMMs) and unbuffered (UDIMMs). ProLiant G7
servers support up to three RDIMMs per channel or up to two UDIMMs per channel. RDIMMs have the
advantage of larger capacities compared to UDIMMs. However, UDIMMs have the advantage of
reduced cost and power use. Your application determines which type of DIMM is best suited for your
server. Note that you cannot mix RDIMMs and UDIMMs together in a server.
On-DIMM thermal sensors
HP-qualified DDR3 DIMMs have an integrated thermal sensor that measures the temperature to within
½°C. Our design engineers use this information to determine the temperature specifications for each
type of DDR3 DIMM under varying conditions. The ―Sea of Sensors‖ fan control technology uses the
temperature information to regulate cooling in the server. Under normal conditions, the iLO 3
firmware monitors the DIMMs’ thermal data and uses a sophisticated algorithm to control the speed of
each fan (see ―Thermal sensors and fan control‖). If a DIMM’s temperature exceeds a design set point
for any reason, the thermal sensors will signal the processor to throttle memory traffic to the DIMMs.
Some third party DDR3 DIMMs may not include a thermal sensor. The BIOS checks all DIMMs during
POST and displays a message if a DIMM does not have a thermal sensor. In this case, the fans will
run at a higher speed, which requires more power.