Intel DX4

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Intel DX4 100 MHz
Voltage converter for DX4 processors (5 V to 3.3 V)
An IntelDX4 FC80486DX4-75 SX883 75 MHz (3× 25 MHz) 16 KB cache L1 WT. It was made in January 1995, and was removed from a Toshiba laptop.

The IntelDX4 is a clock-tripled i486 microprocessor with 16 KB L1 cache. Intel named it DX4 (rather than DX3) as a consequence of litigation with AMD over trademarks. The product was officially named the IntelDX4, but OEMs continued using the i486 naming convention.

Intel produced IntelDX4s with two clock speed steppings: A 75 MHz version (3× 25 MHz multiplier), and a 100 MHz version (usually 3× 33.3 MHz, but sometimes also 2× 50 MHz). Both chips were released in March 1994. A version of the IntelDX4 featuring write-back cache was released in October 1994. The original write-through versions of the chip are marked with a laser embossed "&E", while the write-back enabled versions are marked "&EW". i486 OverDrive editions of the IntelDX4 had locked multipliers, and therefore can only run at 3× the external clock-speed. The 100 MHz model of the processor had an iCOMP rating of 435, while the 75 MHz processor had a rating of 319. The IntelDX4 was an OEM-only product, but the DX4 Overdrive could be purchased at a retail store.

The IntelDX4 microprocessor is mostly pin-compatible with the 80486, but requires a lower 3.3 V supply. Normal 80486 and DX2 processors use a 5 V supply; plugging a DX4 into an unmodified socket will destroy it. Motherboards lacking support for the 3.3 V CPUs can sometimes make use of them using a voltage regulator (VRM) that fits between the socket and the CPU.

S-specs[edit]

Processor speed (MHz) Input clock (MHz) Voltage center (V) Voltage range (V) Part number Clock multiplier S-spec number
75 25× 3 3.3 3.1–3.6 FC80486DX4-75 3× mode only SK052, SX883
100 33× 3 3.3, 3.45 3.1–3.6 FC80486DX4-100 3× mode only SX906
100 33× 3 / 50× 2 3.45 3.3–3.6 FC80486DX4-100 3× or 2× mode SX876
100 33× 3 / 50× 2 3.3, 3.45 3.1–3.6 FC80486DX4-100 3× or 2× mode SK053
75 25× 3 3.3 3.1–3.6 A80486DX4-75 3× mode only SK047, SX884
100 33× 3 3.45 3.3–3.6 A80486DX4-100 3× mode only SK051, SX900
100 33× 3 / 50× 2 3.45 3.3–3.6 A80486DX4-100 3× or 2× mode SX877
100 33× 3 / 50× 2 3.3 3.1–3.6 A80486DX4-100 3× or 2× mode SK050
100 33× 3 3.45 3.3–3.6 A80486DX4WB-100 3× mode only SK096
100 33× 3 / 50× 2 3.3 3.1–3.6 A80486DX4WB-100 3× or 2× mode Limited availability
75 25× 3 3.3 3.1–3.5 A80486DX4WB-75 3× mode only SK102
100 33× 3 / 50× 2 3.3 3.1–3.6 FC80486DX4WB-100 3× or 2× mode SK099
75 25× 3 3.3 3.1–3.5 FC80486DX4WB-75 3× mode only SK100

References[edit]