AMD 5×86

The AMD5×86 is the chip that put AMD onto the map as official Intel competition. While I am mentioning it here on the 486 page of the history lesson, it was actually AMD’s competitive response to Intel’s Pentium-class processor. Users of the Intel 486 processor, in order to get Pentium-class performance, had to make use of an expensive OverDrive processor or ditch their motherboard in favor of a true Pentium board. AMD saw an opening here, and the AM5×86 was designed to offer Pentium-class performance while operating on a standard 486 motherboard.. They did this by designing the 5×86 to run at 133MHz by clock-quadrupling a 33 MHz 486 processor core. This 33 MHz bus allowed it to work on 486 boards. This speed also allowed it to support the 33 MHz PCI bus. The chip also had 16 KB on-die cache. All of this together, and the 5×86 performed better than a Pentium-75. The chip became the de facto upgrade for 486 users who did not want to ditch their 486-based PCs yet.

Here is a list of features, provided by AMD:

• Clock-Quadrupled to 133 MHz
  
• Unified 16K Write-Back Cache
  
• Integrated Power Management
  
• Industry-Standard SMM and Clock Control
  
• 0.35-Micron Process Technology
  
• Lower Power than Pentium-75 or iDX4-100
  
• 32-Bit Scalar x86 Core
  
• Pin-Compatible Packages:
  
• 168-Pin PGA and 208-Pin SQFP
  
• 33-MHz External Bus Speed
  
• Proven x86 Microprocessor Core

While this chip may be fine for many applications, it is really not a wise buy anymore if you can even find one. The 5×86 is unique as the fastest 486 made, but it is relevant only in the pages of the history book now.

Media GX

The MediaGX is an entry level processor built by Cyrix. This chip is different because it is highly integrated. It requires a special motherboard and is not pin compatible with the Pentium. Besides the hassles, though, it was the cheapest route into a Pentium class system available on the market. The price of this chip attracted Compaq to it, and they used it in the Presario 2100 and 2200.

What makes this chip different is its integration. In one chip, Cyrix integrated the processor, based on the old Cyrix 5×86, with the graphics controller, DRAM controller, and PCI bus interface. For this reason, Cyrix has called this chip a “PC on a chip”. The MediaGX, however, was not much of a performer. It was at the lowest end of the Pentium market. It had a low clock speed and had no support for USB, or MMX. It was originally clocked at 120 and 133 MHz, but was later released in 200 and 233 MHz versions.  There is no 3D acceleration on the chip’s display circuitry, so it wouldn’t have been a prime choice for a major game player.

When Via bought Cyrix, National Semiconductor retained rights to the integrated CPUs, including the MediaGX. National took it a little further. The GX1, as it is dubbed, has clock speeds up to 333MHz, supports MMX and USB, as well as added support for some new video formats with the addition of a secondary chip, the CS5530. The two-chip setup has very low power consumption. Given that MediaGX is now a non-entity in the PC world, it has more or less been targeted at the information appliance market. So, as far as the subject matter of this website is concerned, don’t expect us to mention this chip ever again.