What is a Chip Set?
When we speak about busses and system boards, we are also speaking about chip sets. The
chip sets are a bunch of intelligent controller chips, which are on any system board. They are closely tied to the CPU, in that they control the busses around the CPU. Without the chip sets,
neither RAM or I/O busses could function together with the CPU:
Figure 1.1 - The Controller in the Chipset And What Is Used To Control
New Technologies - New Chip Set
Therefore, the chip sets are quite central components on the system boards. When new
technological features are introduced (and this happens continuously) they are often
accompanied by new chip sets. The new chip sets often enable:
- Higher speed on one or more busses
- Utilization of new facilities (new RAM types, new busses, improved EIDE, etc.)
There are several suppliers of Pentium chip sets:
Intel has hitherto been the leader in supplying chip sets to the Pentium system board.
Therefore, let us just mention their chip sets, which have astronomical names.
The Neptune chip set (82434NX) was introduced in June 1994. It replaced the Mercury set
In both chip sets, there were problems with the PCI bus. In January 1995 Intel
introduced the first Triton , where everything worked. This chip set supports some new
features: it supports EDO RAM, and it offers bus master integrated EIDE control and NSP
(Native Signal Processing - one of the many new creations, which was soon forgotten).
Triton first and second
82430FX from late 1995 was Intel's next chip set and the first Triton. In February 1996 the
second generation of Triton arrived. Two new chip sets were introduced: The 82430VX and
82430HX. The last (HX) was the fastest one.
The two sets are similar, yet different. 430HX consists of two chips. It is designed for the more
professional PC's. 430VX consists of four chips. Its cost is slightly lower than HX. It is aimed at
the home use PC market. Let us look at the contents of each chip set:
Common to both chip sets is82371SB, which is a "PCI ISA IDE accelerator chip". It is also
called PIIX3, which some may recognize from the Windows 95 device driver, which comes with
the ASUS T2P4 board.
The chip makes a bridge between the CPU, ISA and PCI bus. The new is, that it permits
concurrent activity in all three locations, thus a new form of multitasking. This is significant for
daily use. All data exchange to and from I/O units cross this intersection, which now has
achieved greater width:
Figure 1.2 -The CPU, ISA, and PCI Bus Controlled By The 82371SB Chipset
New in the chip is also a host function for the USB (Useless Serial Bus), which we have not
seen much use of. Finally, the chip includes EIDE Bus Master control. That means, that EIDE
components like hard disks, to some extent can deliver their data directly to RAM without taking
up CPU time.
Figure 1.3 -
The Intel 82371SB Chipset
Above, you see the 82371SB chip and below, again, its placement relative to CPU and busses:
Figure 1.4 - Placement of the 82371SB Chipset Relative to CPU and Busses
It is generally accepted, that the HX set yields the best performance of the two chip sets
described. But the VX set has two other facilities to offer: Capability for SMBA (Shared Memory
Buffer Architecture). That means among other things, that you can integrate the video card on
the system board with 1 or 2 MB standard RAM, from the working RAM. A technology, which is
used only in the lowest cost PC's.
Also, the VX set also supports the fast RAM type SD-RAM. HX does not. The VX set can
control up to 128 MB RAM, but it cannot cache above 64 MB RAM.
HX controls 512 MB RAM and is the only Intel Pentium chip set to cache above 64 MB RAM. The VX and HX chip sets are out. They are replaced by the TX chip set.
Intel TX Chipset - AGP and Ultra DMA
The newest chip set to Pentium processors are named 82430TX and 82430LX. Both support SD-RAM.
New features are AGP, which is a new high speed graphics bus (Accelerated Graphics Port).
The AGP-bus runs at 66 MHZ - twice the speed of the PCI bus. This gives new power to the
video system, and it frees the PCI bus from all the heavy video work. The AGP adapters also
extend their memory using parts of the mainboard RAM as a bit map cache.
ATA-33 permits EIDE hard disks to transfer at up to 33 MBps - a data volume which no hard
disk can deliver. This improved EIDE standard is also marketed under the name Ultra DMA.
Tests show that Ultra DMA results in a speed increase of 25-75 percent over the traditional
EIDE PIO mode 4. Ultra DMA is the new EIDE standard.
Table 1.1 - The 82430TX and What it Controlled.
The TX set is an update and improvement of the VX set. Relative to this, the TX firstly supports
SD RAM and Ultra DMA hard disks. Two important technologies.But the TX-set cannot cache
above 64 MB RAM, and that is a problem.
Since Intel does not develop new chip sets for Socket7 main boards, it is interesting to follow
companies like Soyo. This the worlds 7th biggest main board manufactor has deloped their own
ETEQ 8236638AT/6629 AGP chipset (ETEQ 6638 for short) which gives new performance
using a bus connecting the CPU with the L2 cache at 100 MHZ. The RAM works at only 66
No more informations available - but tests shows that their board SY 5EH5/M (when do
taiwanese manufactors start naming their products E525 or something to remember?) performs
very well with AMD K6-300 at 3 X 100 MHZ.
VIA Apollo MVP3
This chip set for Socket7 main boards promises very good performance with its 100 MHZ bus
connecting the CPU with the L2 cache and possible PC100 SDRAM. Other features include:
- AGP graphics
- Supports up to 1GB 64Mbit FP/EDO/SDRAM/ PC100
- 2MB L2 cache support
- Virtual Clock Synchronization (VCS) for optimal timin
The Apollo MVP3 chipset consists of a VT82C598AT system controller (476 pin BGA, the
"north bridge") and a VT82C586B PCI to ISA bridge (208 pin PQFP, the "south bridge").
Chip sets for Pentium Pro and Pentium II
The 6th. generation CPU's, Pentium Pro and Pentium II, have their own chip sets. Let us review them chronologically:
This chip set came out in 1995, It is supporting quad CPU configurations. That is PC's with 4
82440FX - Natoma
This chip set can handle 2
CPU's on the same system board.440FX consists of four controllers. As for features, it is like
the 82430HX set. Common for these chip sets is the 82371SB PCI-ISA accelerator, which
provides good performance on the I/O busses.
This is Intel's most widely used chip set for 6th. generation CPU's.
This chip set is good and fast. However, it does not support neither SDRAM, Ultra DMA, or AGP. These features are found in the following chip set 82440LX.
440LX is from August 1997. The new is in AGP and SD-RAM. Thus, this chip set is equivalent
440BX was released on April the 15th 1998. The chip set contains the 82443BX Host Bridge and the 82371EB PIIX4E.
The system bus speed is increased to 100 MHZ. This chip set is is designed for the new
Pentium II chips, which will run at 350, 400, and later 450 MHZ. The 100 MHZ system bus speed is multiplied with clock factors of 3.5, 4, and 4.5.
The chip set promises new and better bandwidth for PCI and AGP using a new Quad Port
technology, which is not explained anywhere. It was expected that the BX chip set should
support the IEEE 1394 bus (FireWire) but it does not yet.
The EX chip set is a discount version of the LX set. The chip set only supports DIMM sockets with up to only 256 MB RAM and just three PCI slots.
To be used with the inexpensive Celeron
Intel will introduce completely new versions of Pentium II using the new Slot 2.
450NX is the first chip set for that allowing 4 or 8 CPU's on the main board using up to 4GB
RAM. An other new feature is the 66 MHZ PCI bus. This chip set is for servers.