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.
|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|
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