AMD 5x86
Encyclopedia
The Am5x86 processor is an x86-compatible CPU
introduced in 1995 by AMD for use in 486-class computer
systems. It was one of the fastest, and most universally-compatible upgrade paths for users of 486 systems.
Introduced in November 1995, the Am5x86 (also known as 5x86-133, Am5x86, X5-133, and sold under various 3rd-party labels such as the Kingston Technology
"Turbochip") is an Enhanced Am486
processor with an internally-set multiplier
of 4, allowing it to run at 133 MHz on systems without official support for clock-multiplied DX2
or DX4 486
processors. Like all Enhanced Am486, the Am5x86 featured write-back L1 cache
, and unlike all but a few, a generous 16 kilobyte
s rather than the more common 8 KB. A rare 150 MHz-rated OEM part was also released by AMD.
Since having a clock multiplier of four was not part of the original Socket 3 design, AMD made the 5x86 accept a 2x setting from the motherboard and instead operate at a rate of 4x. When using an Am5x86, the motherboard must be set to the 2x setting. The chip will actually physically fit into an older 486 socket such as a socket 1 or 2 or the original 168-pin 80486 socket, but doing this requires a replacement voltage regulator, since the AMD chip runs at 3.45 volts.
The combination of clock speed and the relatively large 16 KB write-back L1 cache allowed the 5x86 to equal or slightly exceed an Intel Pentium 75 MHz processor in integer
arithmetic performance. Also, because it was based on a pure 486 design, it was compatible with older systems, something its slightly faster rival, the Cyrix Cx5x86
, had trouble with. The CPU was commonly overclocked to 160 MHz, thereby giving performance similar to that of a Pentium 90 MHz system. It has been reported that some individuals have successfully run the chip at 200 MHz; this would require a PCI-based system (due to the instability of VLB
at high speed) and uncommon motherboard
s and cache RAM
that could cope with a 50 MHz system bus
. There are four main versions of the socketed version of this CPU, manufactured in different locations. There is the common ADW variety, as well as the later ADY, ADZ and BGC. The later models were the preferred versions of the chip, because they were rated for higher temperatures and thus more forgiving of overclocking.
The Am5x86 is also notable for the first-ever use of the controversial PR rating
. Because the 5x86 was the equal of a Pentium 75 MHz processor in benchmarks, AMD later marketed the chip as "Am5x86-PR75".
Sales of the Am5x86 were an important source of revenue for AMD at a time when lengthy delays in bringing the AMD K5
to production were threatening the company's profitability.
AMD manufactured the Am5x86 processor for ordinary PC systems until 1999. It was popular for entry-level desktop systems, appeared in many different notebook models, and also sold separately as an upgrade processor for older 486 systems. Several companies made upgrade kits which packaged an AMD 5x86 with a voltage regulator and socket converter, which allowed its use on almost any 486 motherboard ever produced. The chips were even used on later Acorn
RiscPC "PC card" second processors. The RiscPC's OpenBus only supported a 32-bit memory interface, which meant that the Pentium could not be easily interfaced to it. Intel's expensive Pentium Overdrive
for 486 systems was a troublesome CPU, with many compatibility issues, and so was not used. The 5x86 therefore provided the acme of RiscPC Windows performance.
The chip remained in production for a long time, as it was a popular choice for use in embedded controllers. One derivative of the 5x86 family is the core used in the Élan SC520 family of microcontrollers marketed by AMD.
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
introduced in 1995 by AMD for use in 486-class computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
systems. It was one of the fastest, and most universally-compatible upgrade paths for users of 486 systems.
Introduced in November 1995, the Am5x86 (also known as 5x86-133, Am5x86, X5-133, and sold under various 3rd-party labels such as the Kingston Technology
Kingston Technology
Kingston Technology Company, Inc. is an American privately held, multinational computer technology corporation that develops, manufactures, sells and supports flash memory products and other computer-related memory products. Headquartered in Fountain Valley, California, USA, Kingston Technology...
"Turbochip") is an Enhanced Am486
Am486
The Am486 is a 80486-class family of computer processors that was produced by AMD in the 1990s. Intel beat AMD to market by nearly four years, but AMD priced its 40 MHz 486 at or below Intel's price for a 33 MHz chip, offering about 20% better performance for the same price.While...
processor with an internally-set multiplier
Clock signal
In electronics and especially synchronous digital circuits, a clock signal is a particular type of signal that oscillates between a high and a low state and is utilized like a metronome to coordinate actions of circuits...
of 4, allowing it to run at 133 MHz on systems without official support for clock-multiplied DX2
Intel 80486DX2
The Intel 80486DX2 is a CPU produced by Intel that was introduced in 1992. The i486DX2 was nearly identical to the i486DX but for the addition of clock multiplier circuitry. It was the first chip to use clock doubling, whereby the processor runs two internal logic clock cycles per external bus cycle...
or DX4 486
Intel 80486DX4
The IntelDX4 is a clock-tripled i486 microprocessor with 16 kB L1 cache. Intel named it DX4 as a consequence of litigation with AMD over trademarks...
processors. Like all Enhanced Am486, the Am5x86 featured write-back L1 cache
CPU cache
A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations...
, and unlike all but a few, a generous 16 kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
s rather than the more common 8 KB. A rare 150 MHz-rated OEM part was also released by AMD.
Since having a clock multiplier of four was not part of the original Socket 3 design, AMD made the 5x86 accept a 2x setting from the motherboard and instead operate at a rate of 4x. When using an Am5x86, the motherboard must be set to the 2x setting. The chip will actually physically fit into an older 486 socket such as a socket 1 or 2 or the original 168-pin 80486 socket, but doing this requires a replacement voltage regulator, since the AMD chip runs at 3.45 volts.
The combination of clock speed and the relatively large 16 KB write-back L1 cache allowed the 5x86 to equal or slightly exceed an Intel Pentium 75 MHz processor in integer
Integer
The integers are formed by the natural numbers together with the negatives of the non-zero natural numbers .They are known as Positive and Negative Integers respectively...
arithmetic performance. Also, because it was based on a pure 486 design, it was compatible with older systems, something its slightly faster rival, the Cyrix Cx5x86
Cyrix Cx5x86
Released in August 1995, four months before the more famous Cyrix 6x86, the Cyrix 5x86 was one of the fastest CPUs ever produced for Socket 3 computer systems...
, had trouble with. The CPU was commonly overclocked to 160 MHz, thereby giving performance similar to that of a Pentium 90 MHz system. It has been reported that some individuals have successfully run the chip at 200 MHz; this would require a PCI-based system (due to the instability of VLB
VESA Local Bus
The VESA Local Bus was mostly used in personal computers. VESA Local Bus worked alongside the ISA bus; it acted as a high-speed conduit for memory-mapped I/O and DMA, while the ISA bus handled interrupts and port-mapped I/O.-Historical overview:In the early 1990s, the I/O bandwidth of...
at high speed) and uncommon motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
s and cache RAM
Static random access memory
Static random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...
that could cope with a 50 MHz system bus
Front side bus
A front-side bus is a computer communication interface often used in computers during the 1990s and 2000s.It typically carries data between the central processing unit and a memory controller hub, known as the northbridge....
. There are four main versions of the socketed version of this CPU, manufactured in different locations. There is the common ADW variety, as well as the later ADY, ADZ and BGC. The later models were the preferred versions of the chip, because they were rated for higher temperatures and thus more forgiving of overclocking.
The Am5x86 is also notable for the first-ever use of the controversial PR rating
PR rating
The PR system was developed by AMD in the mid-1990s as a method of comparing their x86 processors to those of rival Intel.-Branding:...
. Because the 5x86 was the equal of a Pentium 75 MHz processor in benchmarks, AMD later marketed the chip as "Am5x86-PR75".
Sales of the Am5x86 were an important source of revenue for AMD at a time when lengthy delays in bringing the AMD K5
AMD K5
The K5 was AMD's first x86 processor to be developed entirely in-house. Introduced in March 1996, its primary competition was Intel's Pentium microprocessor. The K5 was an ambitious design, closer to a Pentium Pro than a Pentium regarding technical solutions and internal architecture...
to production were threatening the company's profitability.
AMD manufactured the Am5x86 processor for ordinary PC systems until 1999. It was popular for entry-level desktop systems, appeared in many different notebook models, and also sold separately as an upgrade processor for older 486 systems. Several companies made upgrade kits which packaged an AMD 5x86 with a voltage regulator and socket converter, which allowed its use on almost any 486 motherboard ever produced. The chips were even used on later Acorn
Acorn
The acorn, or oak nut, is the nut of the oaks and their close relatives . It usually contains a single seed , enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1–6 cm long and 0.8–4 cm broad...
RiscPC "PC card" second processors. The RiscPC's OpenBus only supported a 32-bit memory interface, which meant that the Pentium could not be easily interfaced to it. Intel's expensive Pentium Overdrive
Pentium OverDrive
The Pentium OverDrive was a microprocessor marketing brand name used by Intel, to cover a variety of consumer upgrade products sold in the mid 1990s. It was originally released for 486 motherboards, and later some Pentium sockets...
for 486 systems was a troublesome CPU, with many compatibility issues, and so was not used. The 5x86 therefore provided the acme of RiscPC Windows performance.
The chip remained in production for a long time, as it was a popular choice for use in embedded controllers. One derivative of the 5x86 family is the core used in the Élan SC520 family of microcontrollers marketed by AMD.
Models
| Model number | Frequency | L1 Cache | FSB | Mult. CPU multiplier In computing, the clock multiplier measures the ratio of an internal CPU clock rate to the externally supplied clock. A CPU with a 10x multiplier will thus see 10 internal cycles for every external clock cycle... | Voltage CPU core voltage The CPU core voltage is the power supply voltage supplied to the CPU , GPU, or other device containing a processing core... | TDP Thermal Design Power The thermal design power , sometimes called thermal design point, refers to the maximum amount of power the cooling system in a computer is required to dissipate. For example, a laptop's CPU cooling system may be designed for a 20 watt TDP, which means that it can dissipate up to 20 watts of heat... | Socket CPU socket A CPU socket or CPU slot is a mechanical component that provides mechanical and electrical connections between a microprocessor and a printed circuit board . This allows the CPU to be replaced without soldering.... | Release date | Introduction price |
|---|---|---|---|---|---|---|---|---|---|
| X5-133 ADH | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.45 V | PGA Pin grid array A pin grid array, often abbreviated PGA, is a type of integrated circuit packaging. In a PGA, the package is square or roughly square, and the pins are arranged in a regular array on the underside of the package... -168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |
6 November 1995 | $93 | |
| X5-133 ADY | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.45 V | PGA-168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |
|||
| X5-133 ADZ | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.45 V | PGA-168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |
6 November 1995 | $93 | |
| X5-133 BGC | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.45 V | PGA-168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |
|||
| X5-133 V16BGC | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.45 V | PGA-168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |
|||
| X5-133 W16BGC | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.3 V | PGA-168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |
|||
| X5-133 V16BHC | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.45 V | Surface mounted 208-pin SQFP on PGA-168 | |||
| X5-133 W16BHC | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.3 V | Surface mounted 208-pin SQFP on PGA-168 | |||
| X5-133 SFZ | 133 Mhz | 16 KiB | 33 MT/s | 4 | 3.3 V | Surface mounted 208-pin SQFP on PGA-168 | |||
| X5-150 ADW | 150 Mhz | 16 KiB | 50 MT/s | 3 | 3.45 V | PGA-168 Socket 1 PGA-168 Socket 2 PGA-168 Socket 3 |