Am5x86
AMD-X5-133ADW
Developer	AMD
Manufacturer	AMD
Type	Microprocessors
Introduction	1995 (announced) November 6, 1995 (launch)
Architecture	Enhanced Am486
ISA	IA-32
µarch	80486
Word size	32 bit 4 octets 8 nibbles
Process	350 nm 0.35 μm 3.5e-4 mm
Technology	CMOS
Clock	133 MHz-150 MHz
Package	CPGA-168, SQFP-208
Socket	Socket 1, Socket 2, Socket 3
Succession
←	→
Am486	K5

Am5_x86 (internal codename Am486Plus) was a family of highest performance 486-based microprocessors introduced by AMD in 1995. These processors came with all the features of the Enhanced Am486s but had the highest clock speed available. These chips, which ended up performing similarly and on occasion better than the Pentium-75, became the de-facto upgrade for users with existing 486-based systems. This family solidified AMD position as the official Intel competition.

History

In 1995 AMD was busy working on their first home-grown x86-compatible microarchitecture, K5. As a stopgap solution between the Am486 and the yet-to-be-released K5-based processors, AMD released the Am5x86 family. The name came about due to competitors selling 5th generation-based x86 processors (e.g. Cyrix 5x86) - people were more likely to buy a system with "5" vs "4". AMD took this opportunity to utilize their latest technology and release a final, highest clocked 486 chip for much lower price than their competitor's latest chips. This is very similar to what they had done with their highly successful 40 MHz version of their Am386 family. Later, strong sales of Am5x86 played a crucial role in keeping AMD's profitability while their K5 microarchitecture was experiencing severe delays. AMD continued to sell Am5x86 chips for personal computers until 1999 and for embedded systems well into the 2000s.

Architecture

Contrary to its namesake, the 5x86 was not a "5th-generation x86". Architecturally, the 5x86 is identical to the Enhanced Am486s which included various system and power management features (e.g. SMM & Stop-clock control). Additionally the 5x86 came with the larger 16 KB write-back L1$. The processors were manufactured on AMD's newly upgraded 350 nm process which is what allowed AMD to clock it as high and compete with Intel's low-end Pentiums. AMD had to clock the 5x86 at much higher frequency in order to compensate for its inefficiencies and deliver performance comparable to the Pentium-75. The clock multiplier was set to x4 (e.g. bus speed of 33 MHz would have a core frequency of 133 MHz). Essentially, one can think of the 5x86 as a "Am486DX5-133". In fact, AMD simply sold the Am5x86 clocked under 133 MHz as Enhanced Am486 instead.

Being backwards compatible, the 5x86 could go in the older Socket 1, Socket 2, and Socket 3. However Socket 1/2 both required a replacement voltage regulator as the chips needed 3.45 V to operate. Depending on the motherboard, it either had a manual jumper one has to set or an autodetect version, voltage must be set to 3.45 (± 0.15 tolerance). Likewise the input clock must be set to 33 MHz with a jumper set to quadrupled clock (note that because there is no such provision in the socket, setting the "clock-doubled" setting should cause the CLKMUL pin to be driven high allowing the processor to operate at x4 multiplier). While set to 133 MHz, many in the hobbyist community have reported to have had it overclocked to 160 MHz which would put it at performance similar to the Pentium-90. The later versions had higher package temperature rating, making them easier to be overclocked.

Die Shot

Members

AMD released a 133 MHz version with a multiplier of x4 and a 150 MHz version with a multiplier for x3. Various publications by AMD (including their own BIOS manual) mentioned a 160 MHz version with a multiplier of x4, however that processor was never actually released.

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Am5x86 Processors
Model	Launched	Process	Freq	Mult.	Bus	Max Mem	VCORE	Package	Min Tcase	Max Tcase
AM486DX5-133V16BGC	1997	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.3 V 33 dV 330 cV 3,300 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AM486DX5-133V16BHC	1997	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.3 V 33 dV 330 cV 3,300 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AM486DX5-133W16BGC	1997	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AM486DX5-133W16BHC	1997	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AMD-X5-133ADW	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	55 °C 328.15 K 131 °F 590.67 °R
AMD-X5-133ADY	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	75 °C 348.15 K 167 °F 626.67 °R
AMD-X5-133ADZ	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AMD-X5-133SDW	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	55 °C 328.15 K 131 °F 590.67 °R
AMD-X5-133SDY	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	75 °C 348.15 K 167 °F 626.67 °R
AMD-X5-133SDZ	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AMD-X5-133SFW	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.3 V 33 dV 330 cV 3,300 mV		0 °C 273.15 K 32 °F 491.67 °R	55 °C 328.15 K 131 °F 590.67 °R
AMD-X5-133SFY	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.3 V 33 dV 330 cV 3,300 mV		0 °C 273.15 K 32 °F 491.67 °R	75 °C 348.15 K 167 °F 626.67 °R
AMD-X5-133SFZ	1996	350 nm 0.35 μm 3.5e-4 mm	133 MHz 0.133 GHz 133,000 kHz	4	33 MHz 0.033 GHz 33,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.3 V 33 dV 330 cV 3,300 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AMD-X5-150ADW	1996	350 nm 0.35 μm 3.5e-4 mm	150 MHz 0.15 GHz 150,000 kHz	3	50 MHz 0.05 GHz 50,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	55 °C 328.15 K 131 °F 590.67 °R
AMD-X5-150ADY	1996	350 nm 0.35 μm 3.5e-4 mm	150 MHz 0.15 GHz 150,000 kHz	3	50 MHz 0.05 GHz 50,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	75 °C 348.15 K 167 °F 626.67 °R
AMD-X5-150ADZ	1996	350 nm 0.35 μm 3.5e-4 mm	150 MHz 0.15 GHz 150,000 kHz	3	50 MHz 0.05 GHz 50,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
AMD-X5-160		350 nm 0.35 μm 3.5e-4 mm	160 MHz 0.16 GHz 160,000 kHz	4	40 MHz 0.04 GHz 40,000 kHz	4,096 MiB 4,194,304 KiB 4,294,967,296 B 4 GiB 0.00391 TiB	3.45 V 34.5 dV 345 cV 3,450 mV		0 °C 273.15 K 32 °F 491.67 °R	85 °C 358.15 K 185 °F 644.67 °R
Count: 17

Performance Rating (PR)

Main article: Performance Rating

P-Rating or Performance Rating was a rating system devised by AMD and a number of other manufacturers to equate the performance of their processors with Intel's Pentium equivalent models. While being controversial, the rating scheme allowed users to compare the general performance of the processors under typical load.

Documents

Datasheets

• Am5x86 Microprocessor Family (March, 1996), Publication #19751
• AMD Enhanced Am486 (March, 1997), Publication #20736, includes DX5-133 models

Manuals

• AMD BIOS Development Guide (Enhanced Am486-Am5x86; August, 1995)

Thermal & Clock

• Clock Gating Recommendations; Publication #19195 Revision C/0; August 1995
• CPU Thermal Management; Publication #18448 Revision D/0; August 1995.
• Low Voltage Power Supply Circuits; Publication #19197 Revision D/0; August 1995.
• Phase Lock Loop (PLL) Clock Control; Publication #18495 Revision D/0; August 1995.

See Also

• Am486
• i486