Billy Newsom · 01-01-1997 · Category: Tech-planations

Chipset FAQ

Q: What is the difference between the Intel Chipsets made for Pentium motherboards?

A: There are four Intel chipsets that are commonly found on Pentium motherboards. If your chipset is not here, it is either not made by Intel, it predates Triton, or it is for a notebook PC. One commonality for all of them is a built-in dual channel EIDE controller, indicated by a companion chip called the 82371SB or 82371AB, which is also known as the PIIX controller.

1. 430FX (82437FX & 82438FX): This is the chipset known as the "Triton I" chipset. This chipset is no longer supported, but you can still find a lot of old motherboards that use it. The easiest way to identify the FX is that its motherboards topped usually topped out at about 133 MHz or less, and it didn't support the same type of COAST modules used in later motherboards. It was also known to be buggy and many different versions of this chipset were produced.
2. 430HX (82439HX): The "Triton II" chipset. Think "H" for High-Quality. The HX lacks SDRAM support. The Triton II is superior to all other Intel Pentium chipsets for the following reasons:
   • Support for up to 512 MB of RAM, all of which can be cached. It's not unusual to find 6 to 8 SIMM sockets on a 430HX motherboard.
   • Support for dual processors.
   • Support for parity and ECC RAM.
3. 430VX (82437VX & 82438VX): The "Triton III" chipset. Think "V" for value. None of the features listed for the HX chipset are available for the VX. But the VX has one advantage over the HX: it supports up to 64 MB of SDRAM on 168-pin DIMM's. Both the HX and VX support pipelined burst SRAM, and both perform about 10% faster than the FX. Of course, EDO is supported by the HX and VX. One drawback to the 430VX is that it will only cache the first 64 MB of RAM. If you think that a VX board is to your liking, then look at the latest chipset made by Intel, the 430TX.
4. 430TX (82439TX): The TX chipset is rather new, but it has taken over as the most popular Intel chipset in 1997. First, it's not much faster than the HX or VX. It also shares most of the shortcomings of the 430VX in that it lacks SMP support, it can't use ECC memory, and it won't cache more than the first 64 MB of RAM. It does support 64 MB SIMM's and up to 256 MB of system RAM, but who cares if only 64 MB are cached? It also shares the VX's support for SDRAM. New features include the entire PC/97 recommendations, including:
   • The 82371AB Southbridge. This new PIIX4 controller supports ATA-33 (Ultra DMA) for the next generation of IDE hard disks.
   • Support for new 64 MB SDRAM in 168-pin DIMM's.
   • Support for 128 MB EDO DIMM's.
   • Support for a new power-saving API called DPMA.
   • A single chipset for desktop and notebook PC's. This is a radical concept, because it gives PCI 2.1 support to the laptop users, and the latest power management modes to desktop users. As far as I can tell, the TX replaces the VX and the MX chipset (think "M" for mobile). The 430TX is a 3.3 V chipset, which has caused some problems with certain 5 volt products.

Q: Are there any chipsets that are better than for Intel's?

A: VIA and AMD have teamed up to compete with the latest and greatest Intel PCIset, the 430TX. Their chipset is known as the VIA Apollo VP2/97, or alternately as the AMD-640. It has some major features not found in any of the Triton chipsets, and it also has some similarities to the 430TX.

• Dual processor support.
• Up to 512 MB of RAM, all of which is cachable.
• Up to 2048 KB of pipelined-burst cache.
• SDRAM, EDO, BEDO, and FPM support, including ECC RAM.
• DMA-33 Mode 3 EIDE support.
• ACPI power-savings.
• Built-in RTC (real-time clock), mouse, and keyboard controller.

Q: What are the VIA chipsets called?

A: VIA has Pentium chipsets known as the Apollo Master (570M), VP-1 (580VP), and Apollo VP2/97 (590VP). This link explains the difference between a VP-2 and V2/97 chipset, which is that VIA has enhanced the VP-2 and renamed it the VP2/97, a.k.a. AMD-640.

Q: What about SiS chipsets?

A: SiS has chipsets known as the Genesis 5596/5513, 5597/5598, 5571 Trinity, and the 5511/5512/5513. SiS makes a lot of chipsets with a built-in video controller, including a type of controller that doesn't need seperate video memory. Their chipsets are capable of asynchronous PCI buses and allow for secondary caches larger than Intel's 512 KB limit.

Q: What about Pentium MMX support? Do I have to buy a new TX motherboard or upgrade my BIOS?

A: No, no, no. The chipset has no bearing on whether an MMX Pentium will work, no matter what Intel implies. You will need at least a 66 MHz bus and a 2.5x, 3.0x, or 1.5x clock multiplier to take advantage of the P55C at 166, 200, and 233 MHz respectively. Also, your motherboard needs a 2.8/3.3 V split voltage regulators to use the OEM version, or else you'll have to use an Overdrive version that has its own 2.8 V regulator if your motherboard only has 3.3 V. AMD K6 users will need different voltages depending on the speed of the CPU, plus a BIOS upgrade is often required.

Q: Which chipset supports 75 or 83 MHz?

A: Intel doesn't officially support any bus speed above 66 MHz with its chipsets, although the motherboard manufacturers routinely allow faster speeds. Intel has a point, since the PCI spec does not go beyond 33 MHz, and unless a motherboard uses an asynchronous PCI bus, anything faster than 66 MHz will violate the PCI specification. All Intel chipsets have a synchronous PCI bus. So a 75 MHz memory bus would mean a 37.5 MHz PCI bus, which is a no-no. If you're wondering why people want a 75 MHz bus when Intel Pentiums don't support it, then think about this:

• The Cyrix and IBM 6x86 PR200+ and 6x86MX PR233+ require a 75 MHz bus.
• The Intel Pentium P54C and P55C can be "overclocked" and run at a variety of speeds. This is certainly not supported by Intel, but some people have run Intel CPU's at 262 MHz just for kicks.
• Some people like a faster PCI bus, because this speeds up graphics. Beware that some PCI cards, like hard disk controllers could possibly corrupt data.
• As a final note, VIA does make a chipset called the Apollo VPX/97, which uses an asynchronous PCI bus, and some of SiS's chipsets do, too. This allows you to run the memory bus at 75 MHz, while keeping the PCI bus at 33 MHz. This is not a new idea: in fact, I have on old Pentium 100 motherboard with Opti chipset that had this feature in 1994.

Q: What are the Pentium Pro and Pentium II chipsets called?

A: There are three major chipsets available: the Intel 440FX Natoma, 440LX, and the 450GX Orion. A brief summary of these chipsets is here (5 KB). The 450KX Mars is not a popular chipset, and it is similar to the 450GX.
Only the 440LX supports SDRAM, AGP, and ACPI, but all of them support at least two processors and 1 GB of EDO/FPM RAM. Each chipset besides the 440LX uses the same PIIX3 EIDE controller found in the 430HX and 430VX chipset, meaning they don't have ATA-33 support. The 440LX uses the PIIX4 southbridge, the same one as the 430TX, which gives it the Ultra-DMA support. The 450GX supports four processors and 4 GB of RAM, while the 440FX, 450KX, and 440LX support only two CPU's and 1 GB of RAM.

Q: What is a VXPro, VXTwo, HXPro, or TXPro chipset?

A: Slower clones of the Intel 430VX and 430HX. A large portion of my Chipset Article has focused on these chipsets, which are probably made by PCChips.

Contents

1. CPUs, ROM BIOS, and Chipsets
2. Chipset FAQ
3. Chipset Features