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. This unit was made in January 1995, and was taken from a Toshiba laptop.

IntelDX4 is a clock-tripled i486 microprocessor with 16-kB Level 1 cache.[1] Intel named it DX4 (rather than DX3) as a consequence of litigation with AMD over trademarks. The product was officially named 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 (3× 33.3 MHz). Both chips were released in March 1994. A version of 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 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. 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 the processor. 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.

Specifications[edit]

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

References[edit]