Intel 440BX
Encyclopedia
The Intel 440BX is a chipset
from Intel, supporting Pentium II
, Pentium III
, and Celeron
processors. It is also known as the i440BX and was released in April 1998. The official part number is 82443BX.
The 440BX originally supported Slot 1
and later Socket 370
Intel P6
-based processors in single and SMP
configurations at speeds of up to 1 GHz (and potentially up to 1.4 GHz with certain unsupported modifications, up to 1.7GHz can be achieved using Front Side Bus speeds higher than 133 and appropriate cooling). Its southbridge
counterpart is the PIIX4E.
chipset released by Intel, succeeding the 440FX
and 440LX. With the new 100 MHz front side bus
, Pentium II CPUs were able to scale better in performance by reducing the difference between processor clock and bus speed. The previous 66 MHz bus had become a serious bottleneck and dated back to the first Pentium "Classic" chipsets.
The 440BX had two closely related chipset peers; the 440ZX and 440MX. 440MX is a mobile chipset for laptops, although a number of notebooks did use 440BX. 440ZX is a cost-reduced version of 440BX. It has a lower maximum RAM limit resulting from having support for only 2 RAM banks. The 440ZX-66, designed for Intel Celeron processor, is limited to 66 MHz FSB speed.
The 440BX became one of Intel's most popular chipsets. Enthusiasts enjoyed its overclockability
, with the chipset capable of running the front-side bus at speeds ranging from 66 MHz to well over 133 MHz, in stark contrast to the 440LX's struggle to top 75 MHz. A common overclock involved the pin-40 hack, or using an ABIT BH6 or Asus
P2B, and setting the bus speed on a 66 MHz Covington or Mendocino-core Celeron to 100 MHz. The Mendocino-core Celeron 300A became a "sweet spot" for overclockers, with nearly 100% success rates at reaching 450 MHz on a 100 MHz FSB, allowing it to equate to a much more expensive Pentium II at 450 MHz. Other popular overclocks included the SL2W8-stepping Deschutes-core Pentium II that could often run to 450 MHz at 100 MHz FSB, and the SL35D Katmai-core Pentium III
450 MHz which could frequently manage 600 MHz on a 133 MHz FSB. The later Pentium III Coppermine-core processor was easily overclocked and performed well on 440BX motherboards. Finally, the unsupported Tualatin-core Pentium III could be used with an adapter and various modifications, with varying degrees of success.
Ironically, the 440BX offered better performance than several of its successors. The i810 and i820 chipsets were unable to beat the 440BX at the 100 MHz FSB speed. The i820 was plagued with a requirement for high cost RDRAM
to reach good performance, along with a string of reliability issues involving an SDRAM-to-RDRAM memory translator hub. And, unofficially, the 440BX could often be taken to 133 MHz FSB. Enthusiast motherboards, such as the Asus P3B-F and Abit BH6/BF6/BE6 series, were equipped with BIOS
options to set the board to this unofficial speed. With a 133 MHz FSB, the 440BX could even match the later i815 chipset, which was designed to accommodate the final Tualatin-core Pentium III. Unfortunately, running a 440BX above 100 MHz FSB resulted in the AGP
video card being forced to run on an overclocked AGP bus, as the 440BX only had "2/3" and "1/1" bus dividers. Some video cards were tolerant of this, such as various early NVIDIA GeForce
cards, but more than a few were quite unstable with a 35% AGP overclock.
Still, the later i815 was considered the best Pentium III chipset because it offered a better feature set and very similar performance relative to the 440BX. Not only did the i815 support a proper "1/2" AGP divider for the 133 MHz FSB clock rate, AGP 4x, and Ultra DMA 100, but the later revisions also directly supported the Tualatin Pentium III.
The success of the 440BX chipset has caused various software emulation and virtualization packages to use it as part of their virtual system. VMware
and Microsoft Virtual PC
present the Intel 440BX chipset virtually to hosted virtual machines, due to its broad compatibility.
Chipset
A chipset, PC chipset, or chip set refers to a group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product.- Computers :...
from Intel, supporting Pentium II
Pentium II
The Pentium II brand refers to Intel's sixth-generation microarchitecture and x86-compatible microprocessors introduced on May 7, 1997. Containing 7.5 million transistors, the Pentium II featured an improved version of the first P6-generation core of the Pentium Pro, which contained 5.5 million...
, Pentium III
Pentium III
The Pentium III brand refers to Intel's 32-bit x86 desktop and mobile microprocessors based on the sixth-generation P6 microarchitecture introduced on February 26, 1999. The brand's initial processors were very similar to the earlier Pentium II-branded microprocessors...
, and Celeron
Celeron
Celeron is a brand name given by Intel Corp. to a number of different x86 computer microprocessor models targeted at budget personal computers....
processors. It is also known as the i440BX and was released in April 1998. The official part number is 82443BX.
Features
Slot 1
Slot 1 refers to the physical and electrical specification for the connector used by some of Intel's microprocessors, including the Pentium Pro, Celeron, Pentium II and the Pentium III...
and later Socket 370
Socket 370
Socket 370 is a common format of CPU socket first used by Intel for Pentium III and Celeron processors to replace the older Slot 1 CPU interface on personal computers. The "370" refers to the number of pin holes in the socket for CPU pins...
Intel P6
P6 (microarchitecture)
The P6 microarchitecture is the sixth generation Intel x86 microarchitecture, implemented by the Pentium Pro microprocessor that was introduced in November 1995. It is sometimes referred to as i686. It was succeeded by the NetBurst microarchitecture in 2000, but eventually revived in the Pentium M...
-based processors in single and SMP
Symmetric multiprocessing
In computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...
configurations at speeds of up to 1 GHz (and potentially up to 1.4 GHz with certain unsupported modifications, up to 1.7GHz can be achieved using Front Side Bus speeds higher than 133 and appropriate cooling). Its southbridge
Southbridge (computing)
The southbridge is one of the two chips in the core logic chipset on a personal computer motherboard, the other being the northbridge. The southbridge typically implements the slower capabilities of the motherboard in a northbridge/southbridge chipset computer architecture. In Intel chipset...
counterpart is the PIIX4E.
History and rise to fame
The Intel 440BX is the third Pentium IIPentium II
The Pentium II brand refers to Intel's sixth-generation microarchitecture and x86-compatible microprocessors introduced on May 7, 1997. Containing 7.5 million transistors, the Pentium II featured an improved version of the first P6-generation core of the Pentium Pro, which contained 5.5 million...
chipset released by Intel, succeeding the 440FX
Intel 440FX
The Intel 440FX , is a chipset from Intel, supporting the Pentium Pro and Pentium II processors. It is the first chipset from Intel that supports Pentium II. It is also known as i440FX and was released in May 1996. Official part numbers include the 82441FX and the 82442FX.440FX does not support...
and 440LX. With the new 100 MHz front side 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....
, Pentium II CPUs were able to scale better in performance by reducing the difference between processor clock and bus speed. The previous 66 MHz bus had become a serious bottleneck and dated back to the first Pentium "Classic" chipsets.
The 440BX had two closely related chipset peers; the 440ZX and 440MX. 440MX is a mobile chipset for laptops, although a number of notebooks did use 440BX. 440ZX is a cost-reduced version of 440BX. It has a lower maximum RAM limit resulting from having support for only 2 RAM banks. The 440ZX-66, designed for Intel Celeron processor, is limited to 66 MHz FSB speed.
The 440BX became one of Intel's most popular chipsets. Enthusiasts enjoyed its overclockability
Overclocking
Overclocking is the process of operating a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, but some manufacturers purposely underclock their components to improve battery life. Many people just overclock or 'rightclock' their hardware to...
, with the chipset capable of running the front-side bus at speeds ranging from 66 MHz to well over 133 MHz, in stark contrast to the 440LX's struggle to top 75 MHz. A common overclock involved the pin-40 hack, or using an ABIT BH6 or Asus
ASUS
ASUSTeK Computer Incorporated is a multinational computer technology and consumer electronics product manufacturer headquartered in Taipei, Taiwan. Its product range includes motherboards, desktops, laptops, monitors, tablet PCs, servers and mobile phones...
P2B, and setting the bus speed on a 66 MHz Covington or Mendocino-core Celeron to 100 MHz. The Mendocino-core Celeron 300A became a "sweet spot" for overclockers, with nearly 100% success rates at reaching 450 MHz on a 100 MHz FSB, allowing it to equate to a much more expensive Pentium II at 450 MHz. Other popular overclocks included the SL2W8-stepping Deschutes-core Pentium II that could often run to 450 MHz at 100 MHz FSB, and the SL35D Katmai-core Pentium III
Pentium III
The Pentium III brand refers to Intel's 32-bit x86 desktop and mobile microprocessors based on the sixth-generation P6 microarchitecture introduced on February 26, 1999. The brand's initial processors were very similar to the earlier Pentium II-branded microprocessors...
450 MHz which could frequently manage 600 MHz on a 133 MHz FSB. The later Pentium III Coppermine-core processor was easily overclocked and performed well on 440BX motherboards. Finally, the unsupported Tualatin-core Pentium III could be used with an adapter and various modifications, with varying degrees of success.
Ironically, the 440BX offered better performance than several of its successors. The i810 and i820 chipsets were unable to beat the 440BX at the 100 MHz FSB speed. The i820 was plagued with a requirement for high cost RDRAM
RDRAM
Direct Rambus DRAM or DRDRAM is a type of synchronous dynamic RAM. RDRAM was developed by Rambus inc., in the mid-1990s as a replacement for then-prevalent DIMM SDRAM memory architecture....
to reach good performance, along with a string of reliability issues involving an SDRAM-to-RDRAM memory translator hub. And, unofficially, the 440BX could often be taken to 133 MHz FSB. Enthusiast motherboards, such as the Asus P3B-F and Abit BH6/BF6/BE6 series, were equipped with BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
options to set the board to this unofficial speed. With a 133 MHz FSB, the 440BX could even match the later i815 chipset, which was designed to accommodate the final Tualatin-core Pentium III. Unfortunately, running a 440BX above 100 MHz FSB resulted in the AGP
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...
video card being forced to run on an overclocked AGP bus, as the 440BX only had "2/3" and "1/1" bus dividers. Some video cards were tolerant of this, such as various early NVIDIA GeForce
GeForce
GeForce is a brand of graphics processing units designed by Nvidia. , there have been eleven iterations of the design. The first GeForce products were discrete GPUs designed for use on add-on graphics boards, intended for the high-margin PC gaming market...
cards, but more than a few were quite unstable with a 35% AGP overclock.
Still, the later i815 was considered the best Pentium III chipset because it offered a better feature set and very similar performance relative to the 440BX. Not only did the i815 support a proper "1/2" AGP divider for the 133 MHz FSB clock rate, AGP 4x, and Ultra DMA 100, but the later revisions also directly supported the Tualatin Pentium III.
The success of the 440BX chipset has caused various software emulation and virtualization packages to use it as part of their virtual system. VMware
VMware
VMware, Inc. is a company providing virtualization software founded in 1998 and based in Palo Alto, California, USA. The company was acquired by EMC Corporation in 2004, and operates as a separate software subsidiary ....
and Microsoft Virtual PC
Microsoft Virtual PC
Windows Virtual PC is a virtualization program for Microsoft Windows. In July 2006 Microsoft released the Windows-hosted version as a free product...
present the Intel 440BX chipset virtually to hosted virtual machines, due to its broad compatibility.
External links
- Celeron overclocking FAQ at Ars TechnicaArs TechnicaArs Technica is a technology news and information website created by Ken Fisher and Jon Stokes in 1998. It publishes news, reviews and guides on issues such as computer hardware and software, science, technology policy, and video games. Ars Technica is known for its features, long articles that go...
, by Frank Monroe - Asus P2B-D modification guide
- Intel(R) 440BX AGPset: 82443BX Host Bridge/Controller Datasheet
- Intel 440BX AGPset 82443BX Host Bridge/Controller Specification Update
- 82443BX Host Bridge/Controller Electrical and Thermal Timing Specification Datasheet Addendum