VDD：北桥芯片供电电压或者存储芯片的输入缓冲和核心逻辑的供电电压。

VDDQ:存储芯片的输出缓冲供电电压。

VPP：DDR4中VPP电压的作用是为字位线提供电压，需要外供，DDR4 SDRAM 不用内建 电荷泵Charge pump，为了省功耗；
DDR3本身也需要的，在DDR3 SDRAM内部有电压泵，不需要外供。

VCore: The core supply voltage of an 'important' chip like your CPU or GPU, usually not the Northbridge. Most frequently used to indicate CPU voltage.

VDD: The supply voltage to your Northbridge chip or the supply voltage for the input buffers and core logic of your memory chips (mostly on graphic cards).

VDDQ: The supply voltage to the output buffers of a memory chip.

VTT: Tracking Termination Voltage. Compared to VREF to determine Hi/Lo

VMem: Supply voltage to a memory chip.

VDDR, VDimm: Supply voltage to the memory on your motherboard.

VRef: Reference voltage for the input lines of a chip that determines the voltage level at which the threshold between a logical 1 and a logical 0 occurs. Usually 1/2 VDDQ.

VGPU: The supply voltage to your graphic card's processor.