Modern Motherboard Technology Explained

By: Sandra Prior

Of course, it's one thing to know the theory behind how new technologies can be connected together on a motherboard, but it's another to know where you're going to physically pop your processor, memory and expansion cards. That's handled by the ATX specification, now up to version 2.2. Despite being incredibly dull, it's vitally important and specifies crucial things such as: what size the motherboard can be, where mounting holes are located, power connections, power levels, physical positioning of components, color of connections and so on. Boring maybe, but if vendors decided they'd put these things wherever they liked, it'd be chaos.

Despite being around since 1996, ATX has staved off multiple attempted coups, including BTX, introduced by Intel in 2003 mostly as a result of the soaring power output of the old P4. It offered optimized airflow, a larger heatsink and motherboard area with dedicated low-profile designs. But as the P4 faded, any justification for the increased costs of BTX became extinct as well.

We're seeing ever-increasing drives to lower power consumption and increase efficiency: laptop motherboards use technology that can reduce idle Northbridge power to below 1W, though an entire running desktop system board will suck at least 40W idle, compared to the 10-20W for an entire laptop. The VIA mini-desktop ITX motherboards strike a balance on this front, usually consuming 10-15W in idle and usually less than 20W under full load, but that's hardly ever going to be a realistic choice for the gamer or anyone else that wants to perform other intensive tasks.

Part of the problem is just power regulation, that's pulling the 12v line down to around 1.5v for the processor. Much like PSU efficiency, motherboards have the same problem. Much noise is made about multi-phase voltage regulators: while we're sure they do smooth the voltage in technical terms, they seem to have little real effect. Similarly, new energy regulation modules such as the Gigabyte DES or Asus EPU claim to regulate voltages and perhaps clock speeds more efficiently. These do affect power consumption, perhaps as much as 10w or more at full load.

Despite some shrinkage in the market over the last few years - VIA being sidelined, ULi being bought by NVIDIA and names like ALi and SiS slipping into the background - there's still a lot of choice if you're after a new motherboard. Higher levels of integration mean you get more for your money; budget boards come packed with features while today's high-end boards come bristling with exotic extras, to the point of confusion and pointlessness.

Intel remains the leading chipset supplier: about half the world's motherboards have ‘Intel Inside’. It's also a technology leader, bringing new developments such as PCIe v2, SATA 2 first to boards in new chipsets. It has used the Memory Controller Hub (MCH) as the Northbridge and the I/O Controller Hub (ICH) for the Southbridge ideology since the debut of the P4. ICH9 is the current mainstream Intel Southbridge and supports up to 12 USB 2.0, six SATA, two eSATA and twin Gigabit network ports, plus high-definition audio and six single PCIe lanes. Extra options can supply hardware RAID and Turbo Memory. ICH10 is just becoming available but adds little to the party: you should note there are no PATA channels at all.

Robson technology, now branded Turbo Memory, was supposed to increase drive performance, but real-world results are disappointing. ICHl0 introduced User Pinning so it's possible to permanently store an application in the flash memory. This could have been an interesting development, but it has been somewhat overshadowed by the likes of Asus Express Gate that enable you to boot into a ‘Virtual Appliance Environment’ (VAE) featuring a basic GUI, a browser based on Firefox 2.0 and a Skype VolP client in less than six seconds, courtesy of a compact Linux distribution. This 'instant-on' OS offers many advantages: it's able to run on PCs where the hard disk is absent or malfunctioning, and is less vulnerable to malware as the system is mostly read-only. Already a feature of the Eee Box and nine others, Asus will be extending Express Gate to its whole range in 2009. Intel's high-end option remains the X range; the X48 is the only motherboard to officially support the 1600FSB for both DDR3 and Core 2 Extreme Edition. In reality though, most available X38 motherboards can actually offer this support anyway, as well as the XMP for enhanced memory performance profiles. It also offers two l6-lane PCIe v2 slots for CrossFire support.

A similar situation can be applied to the new P45 that replaces the P35. At least it does introduce PCIe v2 and optionally supports three graphics slots, but as it's positioned as a mainstream chipset, it's hardly required at this point. If your modules support it, Intel XMP memory technology will mean you get the best performance out of them.

NVIDIA has always made a point of offering both Intel and AMD options. Currently, its 790i Ultra SLI with its top-end Intel chipset, boasts: PCIe v2, support on two full 16-lane graphics slots and a third PCIe vl 16-lane slot, DDR3 up to 2000MHz and 1600FSB support. The accompanying MCP Southbridge offers an additional 12 lanes of PCIe, twin Gigabit ports, ten USB ports, high-definition audio, six SATA and two PATA ports and even a PCI bus.

Unlike the Intel chipsets, NVIDIA has opted for DDR3 only, firmly encamping at the high-end. It of course offers the NVIDIA ‘SLI-Ready Memory’ technology for EPP memory support. For people requiring DDR2 support, the 780i still offers triple SLi in a largely similar configuration to the 790i and the 750i with its ‘Vanilla’ PCIe v2 SLi support.

With its AMD range of chipsets NVIDIA's entire range sports integrated graphics - DirectX 10, HDMI and HDCP-compatibility. We guess the lack of a memory controller on the Northbridge helps when things get busy, almost like having a spare room in the house. The 780a is its high-end option and supports three-way SLi - again, via two PCIe v2 and a single v1 16-lane slots. Oddly, the SLi support hangs off the Southbridge, that being its sole job. The usual Southbridge connections are on the Northbridge, offering 12 USB 2, six SATA, two PATA and Gigabit port, plus high-definition audio and three more PCIe v1 lanes.

For mid- and entry-level buyers, the NVIDIA 8300/8200 chipsets are the perfect choice. Identical in everything but graphics speed, these are single chipset solutions, offering the same abilities as the 780a but with only a single 16-lane PCIe v2 slot. This is somewhat balanced via the Hybrid SLi feature that uses the onboard graphics to accelerate graphics or save power. The Hybrid mode only works with the 8400GS and 8500GT cards, which makes sense for low-end options.

Finally, what about AMD? It's still pushing its high-end 700 chipset, and has rebranded the ageing Xpress 3200 and Xpress 1600 ranges to the 580X and 480X to eliminate any confusion from their Intel-compatible counterparts. The high-end 790FX (launched at the end of 2007) is still something of a power-house. It supports two physical CPU sockets -rare in real-life - along with 42 PCIe v2 lanes enabling four-way CrossFire fun via two full 16-lane and two 8-lane slots. Oh, and twin Gigabit ports - yes, it's a fairly feature-heavy Northbridge, alright. Odd, then, that it was typically paired with the comparatively weak SB600 Southbridge, offering only four SATA ports, an extra four PCIe v1 lanes, RAID, two PATA channels and 10 USB 2.0 ports. Happily, this is being superseded by the SB700/750, with six SATA ports, eSATA support, 14 USB ports and support for hybrid flash drives.

For more mid-range systems, AMD's 790X supports two physical CrossFire slots and the new 780G. This last chipset is of interest as it comes with integrated graphics and offers similar features to the NVIDIA 8300/8200 chipsets. The Hybrid CrossFire works alongside a HD2400 or HD3450 graphics card for about 50 per cent increases in 3D speed. Those will remain on the market for a good while. New high-end options such as the Intel X58 and the AMD 800 series are on the way with new sockets and better memory support, but not until the beginning of 2009.