UMC Green CPU

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UMC U5SX, 33 MHz.

The UMC Green CPU was both an 80486 processor family from United Microelectronics Corporation (UMC) and a copy of the Intel i486 .

U5S

Command and socket compatible with the Intel i486SX .
Also sold as U5SD and U5SX.

Technical specifications

UMC Green CPU U5S with 33 MHz.
Die-Photo of an opened UMC U5S-SUPER33
  • L1 cache: 8 KB
  • L2 cache: depending on the mainboard or chipset used
  • CPUID: 4-2-3
  • FPU: no
  • Socket 3 with an FSB of 25, 33 or 40 MHz
  • Operating voltage (VCore): 5V (Low-Voltage (LV): 3.3V)
  • Housing: CPGA, PPGA (U5SP), PQFP (U5SF, including adapter)
  • Release DATE: 1994
  • Manufacturing technology: 0.6 µm
  • The size:? mm² with 1.2 million transistors
  • Clock rates:
    • 25 MHz (also as -Super25)
    • 33 MHz (also as -Super33)
    • 40 MHz (also as -Super40)
  • Power consumption at 33 MHz:
    • 2.25W at 5V
    • 0.76W at 3.3V (U5S LV)

Trivia In measurements, the U5S achieved a performance gain of around 15 percent on average compared to an Intel 486SX33. The retail price for 1000 pieces was quoted as $ 70 / $ 50 for the 33/25 MHz model.

U5D

Comparable to the Intel i486DX

Technical specifications

  • L1 cache: 8 KB
  • L2 cache: depending on the mainboard or chipset used
  • Socket 3 with an FSB of 25, 33 or 40 MHz
  • Operating voltage (VCore): 5V
  • Release DATE: 1994
  • Manufacturing technology: 0.6 µm
  • The size:? mm² with 1.2 million transistors
  • Clock rates:
    • 25 MHz (also as -Super25)
    • 33 MHz (also as -Super33)
    • 40 MHz (also as -Super40)

U486DX2

Comparable to the Intel i486DX2.

Model data

The vendor ID string of these CPUs is UMC UMC UMC .

Dispute with Intel

In Intel's view, UMC violated its own patents with the CPU and therefore sued the competitor. A sales ban was reached in the USA and for this reason the words "Not for US sale or import" are clearly visible on the CPUs. Although the CPUs were sold outside the US, the disputes with Intel and the rather poor performance were an obstacle to a great market success. UMC finally came to an agreement with Intel and in return for payment of a larger sum of money, UMC waived to manufacture x86 CPUs in the future, while Intel withdrew all lawsuits against UMC.

See also

Web links

Commons : UMC microprocessors  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f g Georg Schnurrer: Noch'n Gedicht In: ct Magazin für Computertechnik No. 9, 1994, p. 27.