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Heir To The BX: 18 Pentium III Motherboards Using The 815 Chipset

The 815 Chipset

With the introduction of the 820 and 840 chipsets, Intel wanted to replace SDRAM-memory with the much more expensive and questionably performing RDRAM. Thanks to several embarrassing mistakes - e.g. 'Caminogate' and the MTH issue - the i820 and i840 chipsets never became successful. RDRAM based systems have still not proven to be able to beat SDRAM machines, particularly not at the same price point. Only dual-channel RDRAM computers with Intel's 840 chipset can provide better performance in some workstation applications, but at much higher prices.

Actually, the 815 chipset is not only replacing the good old 440BX chipset, but can also be seen as inexpensive and fast alternative to the rather useless 820 chipset. In addition, its integrated graphics makes an AGP graphics card obsolete for people who only run office applications. Still you have got the option to supply your own AGP 3D-accelerator as well. i815 offers most of the important goodies of i820, but it lacks dual processor support and it can't host more than 512 MB of memory. i810 forces you to use its integrated graphics solution and it only supports PC100 SDRAM, so it's far from an alternative to either i820 or i815, unless you are into building an inexpensive system with average to low performance

If there wasn't the rather high price and limited supply, i815 could be an excellent choice for system integrators: Intel chipset, good performance, no need for a graphics card, inexpensive on-board sound and network solutions and it is easy to upgrade.

The GMCH (Graphics and Memory Controller Hub), former North Bridge, is the first of two essential elements of the 815 chipset. It includes the CPU interface, SDRAM controller, graphics controller and external AGP interface and a power management controller. The motherboard manufacturer has the choice of two different ICH chips (I/O Controller Hub, former South Bridge) to go with the 'GMCH'. The 82801AA supports UltraATA/66 and two USB ports. Its bigger brother, the 82801BA, supports UltraATA/100, four USB ports, a high priority PCI interface for 1394-controllers, integrated LAN controller and runs at 1.8 instead of 3.3 V. The following table will show you all differences:

Feature82801AA (ICH)82801BA (ICH2)
PCI6 Masters6 Masters; High Priority Option for 1394
IDE InterfaceUltra ATA/66Ultra ATA/100
USB Host Controller1x UHCI (2 Ports)2x UHCI (2 Ports)
LAN ControllerNone10/100 Mbit
Package241-pin BGA, 3.3 V360-pin EBGA, 1.8 V
ISA-Supportover ext. bridgeover ext. bridge

What About AMR And CNR?

On most i815-motherboards you might either find Audio/Modem Riser or Communications and Network Riser slots. I think the descriptions already give away what those components are good for, so I am not going to start an excursion into these two slots. The idea might be good, but in reality it is almost impossible to get an AMR or CNR modem. In my opinion, choosing a PCI device is the best you can do, because you can keep using this card for some years to come. Maybe your next motherboard will not have the AMR or CNR slot anymore, which might force you to get a PCI model anyway.

AMR and CNR are targeted to OEMs, who always try to find the least expensive way of adding features to their systems. People who build their own systems should not bother with this stuff and motherboards that are targeted to the retail market can do just fine without CNR or AMR slots.

Memory Matters

There is one issue, which might cloud the bright picture of Solano, as it is restricted to 512 MByte RAM only. That should be enough for most of us, but high-end video or audio applications eat RAM like a horse. In that case, the VIA 694X chipset might be the better choice.

As the memory clock can only be either 100 or 133 MHz, you will finally have to kiss goodbye to any 66 MHz SDRAM DIMMs. There are several ways of clocking your system and memory:

Front Side BusCPUMemory Clock
66 MHz FSBIntel Celeron (300-733 MHz)100 MHz
100 MHz FSBIntel Celeron FC-PGA (533-733 MHz) overclockedIntel Pentium III (550-850 MHz)VIA Cyrix III (500-600 MHz)100 or 133 MHz
133 MHz FSBIntel Pentium III (533-1000 MHz)VIA Cyrix III (500-600 MHz)100 or 133 MHz