Power Rails (Original)

For Xbox 360 S and Xbox 360 E, see Power Rails (S/E).

The Original Xbox 360's motherboard has various rails which power components of the system.

This page applies to the Xenon, Zephyr, Falcon, Elpis, Jasper, and Tonasket motherboards.

Standby Power

V_1P8STBY

• Voltage: 1.8V
• Source: V_5P0STBY

V_3P3STBY

• Voltage: 3.3V
• Source: V_5P0STBY

V_5P0STBY

• Voltage: 5V
• Source: Power Supply

Main Power

V_12P0

• Voltage: 12V
• Source: Power Supply
• Multipurpose System Power

V_1P8

• Voltage: 1.8V
• Source: V_5P0 or tied to V_MEM
• Multipurpose System Power

V_3P3

• Voltage: 3.3V
• Source: V_12P0
• Multipurpose System Power

V_5P0

• Voltage: 5V
• Source: V_12P0
• Multipurpose System Power

V_5P0DUAL

• Voltage: 5V
• Source: V_5P0 or V_5P0STBY, controlled by SMC
• Purpose: USB Port Power

V_CPUCORE

• Voltage: 1.1-1.4V, controlled by CPU via APS
• Source: V_12P0
• Purpose: CPU Power

V_CPUPLL

• Voltage: 1.8V
• Source: V_3P3 or tied to V_1P8
• Purpose: CPU PLL Power

V_CPUVCS

• Voltage: 1.32-1.68V, controlled by CPU via APS (CPU VID * 1.2)
• Source: V_5P0
• Purpose: CPU VCS Power
• Not present on Xenon, Zephyr, and Elpis

V_EFUSE

• Voltage: 3.5V
• Source: V_5P0
• Purpose: CPU eFUSE Power

V_GPUCORE

• Voltage: 1.075-1.150V, controlled by VID strapping
• Source: V_12P0
• Purpose: GPU and eDRAM Power

V_GPUPCIE

• Xenon, Zephyr, Falcon, and Elpis
  • Voltage: 1.25V
  • Source: V_3P3
• Jasper and Tonasket
  • Voltage: 1.075
  • Source: Tied to V_GPUCORE (Jasper and Tonasket)
• Purpose: GPU PCIe Power

V_MEM

• Xenon, Zephyr, Falcon, and Elpis
  • Voltage: 1.9-2.1V, controlled by strapping depending on RAM type
• Jasper and Tonasket
  • Voltage: 1.8V
• Source: V_12P0
• Purpose: RAM Power

V_MPORT

• Voltage: 3.3V
• Source: V_5P0
• Purpose: Memory Unit Port Power

V_SBPCIE

• Voltage: 1.87V
• Source: V_3P3
• Purpose: Southbridge PCIe Power