HP ProLiant DL360e Configuring and using DDR3 memory with HP ProLiant Gen8 Ser - Page 18

Figure 9: Throughput by DIMM Type at 1 and 2 DIMMs per channel. Throughput (GB/s) Throughput by DIMM Type At 1 and 2 DIMMs per channel 90 85 80 75 70 65 60 55 50 2R 1333 UDIMM 2R 1333 RDIMM 2R 1600 RDIMM 1 DIMM / channel 2 DIMMs / channel Throughput benefits of two DIMMs per Channel at 1333 MT/s Although Intel's design supports two UDIMMs per channel running at 1066 MT/s, HP has engineered ProLiant Gen8 servers to reliability operate at 1333 MT/s with 2 DIMMs per channel when using HP SmartMemory. Enabling 2 UDIMMs per channel at 1333 MT/s increases throughput by about 22% and decreases loaded latency by 34% over 2 DIMMs per channel operating at 1066MHz Table 12: Increased throughput with two 4GB 2R LV UDIMMs per channel at 1333 MT/s versus 1066 MT/s 2 DPC @ 1066 MT/s 2DPC @ 1333 MT/s Delta Throughput (GB/s) 59.55 72.30 22% higher Idle Latency (ns) 65.34 64.97 .5% lower Loaded Latency (ns) 196.40 129.20 34% lower Idle Power (16 DIMM) (W) 2.40 2.40 0% Loaded Power (16 DIMMs) (W) 30.93 39.57 28% higher Power benefits of multiple DIMMs per channel at 1.35V HP has also engineered its DDR3 memory to operate at lower voltage than standard industry memory. HP SmartMemory RDIMMs can operate at 1.35V at three DIMMs per channel (3 DPC) at 1066 MT/s. Standard RDIMMs must operate at 1.5V at three DIMMs per channel. As shown in Table 13, 3 DPC operation at 1.35V in a saves almost 20 watts of power in a fully configured 24 slot server. 18