SOYO RX 580 8Gb

Seller Note “VRAM issue” (not detected would be more accurate)


  • Superficially looks like a cheap XFX RX 580, without a backplate
  • Decent condition, with the original box, bought for £20.98 (curiosity buy!)
  • Resistances
    • VCore – 1.9Ω
    • VMem – 93.5Ω
    • VDDCI – 38.7Ω
    • Display Rail – 42Ω
    • 5V – 824Ω
    • 1.8V – 2.3KΩ
    • 3.3V – 2.3KΩ
    • 12V – 4.5KΩ+ (slot), 2.3KΩ+ (8 pin)
  • Power on testing
    • Not detected
    • Has 5V, but missing 1.8V and all derived voltages e.g. Display Rail, VDCCI, VMem, VCore

Investigating missing 1.8V rail

Taking a look at the 1.8V LDO we have a uP8801S

VIN (pin 3) is present at 3.3V, but EN (pin 2) is very low at 0.044V

Need to investigate the circuit driving the enable volatge