The HS22 with Intel Xeon 5600 series processors supports 1.35 V or 1.5 V DIMMs. Low-power 1.35-volt memory DIMMs is a feature supported for the HS22 using the Intel Xeon 5600 series processor only. The ability to run two DIMMs per channel (2DPC) at 1333 MHz is a feature supported for the HS22 using the Intel Xeon 5600 series processor only. If the low-power 1.35-volt DIMMs are installed with standard 1.5-volt DIMMs, then these low-power DIMMs also operate at 1.5 volts and thus lose their energy-efficient capability. For models with the Xeon 5600 processor: 1.35-volt DIMMs operate at 1.5 volts if you enable 2DPC at 1333 MHz in UEFI. ow-power 1.35-volt DIMMs support 1DPC at 1333 MHz or 2DPC at 1066 MHz, whereas 1.5-volt DIMMs support 2DPC at 1333 MHz (provided that the processor also supports these memory speeds).