NOTE: The information provided below is for a Cyrix product that is no longer in production.

• Processor Brief

• Is the Cyrix 486DX2 processor still available?
• What does DX2 mean?
• If DX2 is clock doubled, is a DX4 processor "clock quadrupled?"
• What does the "v" mean on the Cyrix 486DX and DX2 microprocessors?
• The DX4-100 processor doesn't contain the "v" designation for low power. Does this mean it's not a low power processor?
• What are the proper jumper settings for the Cyrix 486 CPUs?
• Will the Cyrix chip run as fast as the Intel part?
• How will CPU benchmarks such as Landmark and Norton rate the Cyrix CPU against the Intel or AMD parts?

Q. Is the Cyrix 486DX2 processor still available?

A. No. The Cyrix 486DX/DX2/DX4 processors are no longer in production or sold by Cyrix.

Q. What does DX2 mean?

A. A 486 processor with a DX2 identification, such as 486DX2/xx, means that it is a "clock doubled" microprocessor. If we use the DX2/50 as an example, the processor itself is running at 50 MHz while the system or motherboard is running at 25 MHz. Hence, the CPU is running at twice the speed of the board and is called clock doubled.

Q. If DX2 is clock doubled, is a DX4 processor "clock quadrupled?"

A. Processors like the Cyrix 486DX4-100 are "clock-tripled." The DX4-100 runs at 100MHz while the external bus speed runs at 33 MHz.

Q. What does the "v" mean on the Cyrix 486DX and DX2 microprocessors?

A. The "v" in, for example, the Cyrix CX-486DX2v-66 means that it is low voltage CPU made to go into notebook computers or other systems that require lower voltage parts or use power management features.

Q. The DX4-100 processor doesn't contain the "v" designation for low power. Does this mean it's not a low power processor?

A. Unlike the DX2 processors, the Cyrix 486DX4 processors were designed as low-power performance processors for notebook PCs. The DX2 processors were originally introduced as 5-volt CPUs, later moving to 3-volt technology.

Q. What are the proper jumper settings for the Cyrix 486 CPUs?

A. You will need to consult your motherboard manual for a complete answer to that question. New motherboards have jumper settings that allow all the features of the Cyrix chip to be used. If the proper jumper settings are not selected, the chip may run fine but some Cyrix features may not be implemented.

Q. Will the Cyrix chip run as fast as the Intel part?

A. The Cyrix 486DX2 processor has comparable DX2 performance. If your system supports the write-back cache architecture, then it could run significantly faster than a comparable 486 system. The Cyrix 486DX4 processor with an 8K write-back cache has comparable DX4 performance, and in some benchmarks outperforms Intel's DX4 with 16K write-through cache.

Q. How will CPU benchmarks such as Landmark and Norton rate the Cyrix CPU against the Intel or AMD parts?

A. Synthetic benchmarks will vary because of the sampling of instructions used to run the CPU tests. The most important tests are application-based benchmarks such as Ziff-Davis Winstone® 95 that test the entire system while running real-world applications.