Intel DX4
The IntelDX4 is a clock-tripled i486 microprocessor with 16 KB L1 cache.[1] 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 (3× 33.3 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
| 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 |