The gateway between a processor and other components is a set of interface controllers generically called the chipset. Traditional chipsets include a northbridge with memory controller and graphics card interface and a southbridge with slower expansion card interfaces and various peripheral, storage, and communications controllers. The only remaining mainstream platforms that still fit the traditional description are based on Intel’s LGA 775.
AMD was first to remove the memory controller from its chipsets and put it on the CPU in its Socket 754 launch back in 2003. Intel followed the move with its LGA 1366 interface in 2008. The company further integrated with its LGA 1156 platform by moving the primary graphics interface controller (PCIe 2.0) to the CPU, and then released dual-core LGA 1156 processors with the on-board graphics engine that was previously found in value-oriented northbridges.
AMD Northbridge Options
AMD’s 700-series chipsets provide a multitude of options for both discrete (no onboard graphics) and integrated graphics customers. Northbridge products include:
- 790FX, with 42 PCIe 2.0 links, the best match for multiple graphics cards.
- 790X, a lower-cost 26-lane version of the 790FX that supports a single graphics card with 16 lanes or two cards with eight lanes per card.
- 790GX, an integrated-graphics version of the 790X that supports discrete graphics, integrated DirectX 10.0 graphics, and combinations of AMD discrete cards with integrated graphics.
- 785G, an updated version of the 780G that supports DirectX 10.1 and HDMI 1.3.
- 780G, a lower-cost version of the 790GX that supports a single AMD graphics card and integrated graphics simultaneously for enhanced multi-monitor support.
- 780V, a lower-cost version of the 780G that supports fewer graphics features.
- 770, a version of the 780G that has no integrated graphics and supports a single graphics card in true x16 mode. An additional graphics card can be hosted at reduced bandwidth by using four of the chipset’s x1 pathways.
- 760G, a version of the 780G with a reduced-performance graphics engine that supports integrated and discrete graphics, but not simultaneously.
- Older models such as the 740G that do not support the higher-speed HyperTransport connection of AM2+ and AM3 processors.
AMD Southbridge Options
AMD’s introduced SB700-series southbridges after several motherboard models had already been released using a combination of newer and older parts. Modern designs use the SB700 series exclusively.
- SB750 adds the RAID 5 user option to the SB710’s feature set, and is reputed to offer better SATA and USB performance than previous models.
- SB710 adds Advanced Clock Calibration (ACC) and integrated control of legacy I/O ports to the SB700’s features. ACC is used by overclockers to improve the scalability of some processors (first-generation Phenoms), and/or to enable cores that were disabled during the manufacturing process.
- SB700 supports up to six SATA drives at 3.0 Gb/s in legacy mode, AHCI mode, and RAID modes 0, 1, and 10. Two Ultra ATA drives are also supported at up to 133 MB/s, along with 12 USB 2.0 devices
Nvidia Chipsets for AMD Processors
Nvidia also produces several options to support AMD processors in both discrete (no graphics) and integrated graphics versions. For discrete-graphics customers, the use of an Nvidia chipset is required to unlock the SLI feature of Nvidia graphics cards, while integrated graphics customers will be more interested in the firm’s onboard graphics alternatives. Northbridge products include:
- nForce 980a SLI, which adds a second integrated network controller and DDR3 support for onboard graphics, compared to the 780a SLI.
- nForce 780a SLI adds the nForce 200 bridge to 750a SLI features, supporting two graphics cards in true x16 mode, four x16 cards in x8 mode, or a combination of x16 and x8 pathways across three slots.
- nForce 750a SLI adds SLI capability for two discrete graphics cards, each in x8 transfer mode, compared to the GeForce 8300 on which it’s based. Because the 750a SLI targets a higher-priced graphics market, its integrated graphics engine is primarily intended to be used for automatic switching between discrete and integrated graphics engines to save energy.
- nForce 740a SLI removes integrated graphics compared to the 750a.
- nForce 730a removes SLI support compared to the 740a.
- GeForce 8300 mGPU, a single-component integrated chipset that supports onboard graphics plus a single PCIe graphics card simultaneously. The design is intended to allow the addition of a low-cost GeForce graphics card, operating in concert with the onboard graphics engine to boost graphics performance. The GeForce 8300 chipset also supports three PCIe x1 devices or expansion slots, has a separate pathway for its integrated Ethernet controller, and has interfaces for up to 12 USB 2.0 devices.
- GeForce 8200 mGPU, a reduced-performance version of GeForce 8300
- GeForce 8100 mGPU, a reduced-feature version of the GeForce 8300 that removes its ability to support parallel operation with an additional GeForce graphics card.
Intel Chipsets for LGA 1156
Because all northbridge functions have been moved onto LGA 1156 processors, compatible motherboards feature only a southbridge that Intel has re-labeled PCH (platform controller hub).
- P55 Express features eight half-speed (2.5 Gb/s) PCIe 2.0 lanes, 14 USB 2.0 ports, and six SATA 3.0 GB/s ports. Intel enables pathway splitting for the full-speed PCIe 2.0 controllers of all LGA 1156 processors when paired with the P55 Express, so that any processor can support a single card with 16 lanes or two cards with eight lanes each. ATI CrossFire and Nvidia SLI are enabled for this chipset through graphics drivers and RAID modes 0, 1, 5, and 10 are also enabled.
- Q57 Express enables the graphics engine of integrated-graphics processors, such as the Core i3 and dual-core Core i5 processors, but disables pathway splitting for the processor’s integrated PCIe controller. Intel Active Management Technology (AMT) 6.0 is also enabled for easier administration in large office environments.
- H57 Express enables the onboard graphics engine of processors that have it, but disables pathway splitting for the processor’s PCIe controller. RAID modes 0, 1, 5, and 10 are retained, but AMT 6.0 is disabled.
- H55 Express retains most of the features from the H57 Express, but disables onboard RAID capability.
Intel Chipsets for LGA 1366
The single desktop chipset that exists for Intel LGA 1366 processors is Intel’s X58 Express. Featuring a super-fast QPI link between the CPU and chipset similar to the one used internally with later LGA 1156 processors, the X58 northbridge provides 36 lanes of PCIe 2.0 connectivity to support two graphics cards in x16 mode, four in x8 mode, or a combination of one x16-mode and two x8-mode slots. An additional card can be served by the X58’s four remaining PCIe 2.0 lanes and the associated ICH10R southbridge adds another six lanes (at PCIe 1.1 mode).
Already a classic part when the X58 Express was launched, the ICH10R southbridge also supports a separate pathway for Intel’s gigabit Ethernet MAC, 12 USB 2.0 ports, and six SATA 3.0 Gb/s drives configurable to legacy, AHCI, and RAID modes 0, 1, 5, and 10.
Intel Northbridge for LGA 775
The last mainstream and high-end chipsets to include a memory controller all support Intel’s declining LGA 775 platform. A few of Intel’s northbridge options include:
- P45 Express, the most recent mainstream LGA 775 chipset for discrete graphics cards, was also Intel’s first mainstream part to support splitting its 16 PCIe 2.0 lanes across two cards at x8 transfers if desired. The chipset officially supports CPU bus speeds of 200, 266, and 333 MHz at a quad-data rate, labeled FSB-800, FSB-1066, and FSB-1333, though it contained all the proper chipset and memory ratios for stable use at FSB-1600. DDR2-800 and DDR3-1066 are officially supported, although additional memory multipliers allow unsanctioned use of memory data rates up to the chosen FSB data rate.
- P43 Express limits the northbridge PCIe 2.0 controller to a single card.
- G45 Express adds Intel’s GMA X4500HD graphics engine to the list of P45 Express features.
- G43 Express removes HD video acceleration from the G45’s feature set.
- G41 Express reduces maximum supported memory from 16 to 8GB and demotes the PCIe controller mode from revision 2.0 (5.0GT/s) to revision 1.1 (2.5GT/s).
- Q45 Express adds Intel vPro Technology to the list of G43 features for easier administration in large office environments.
- Q43 Express provides G45 features to the business market.
- X48 Express, a rebadged version of the X38 Express that was validated by Intel to support FSB-1600, is functionally identical to the earlier part. Few DDR2 motherboards exist for the X48 Express, partly because of a myth that the chipset supports only DDR3, discouraging buyers from seeking out DDR2 motherboard models. As part of the FSB-1600 validation, DDR3-1600 was added to its list of supported memory types.
- X38 Express features official support for FSB-800, FSB-1066, and FSB-1333, but also contains the proper chipset and memory ratios for FSB-1600, which had not yet been validated at the time of its release. As such, its official memory support is also limited to DDR3-1333, although users who chose to ignore its lack of FSB-1600 validation also found DDR3-1600 functionality. A total of 32 PCIe 2.0 lanes support up to four graphics cards in x16 or x8 modes, depending on how many slots are configured for use. Fewer DDR3 models exist than DDR2, partly because of a popular myth among buyers that X38 was a DDR2-only chipset.
- P35 Express supports FSB-800, FSB-1066, and FSB-1333, along with DDR2-667, DDR2-800, and DDR3-1066 memory. Additional settings on some motherboards make higher memory data rates available at up to FSB data rates. A single graphics card is supported at a PCIe 1.1 transfer rate across 16 lanes, although some motherboards add support for a second x16 graphics card via four lanes from the southbridge.
- G35 Express adds Intel’s GMA X3500 graphics engine and removes DDR3 capability compared to the P35 Express. The relative weakness of its integrated graphics best suits light tasks, such as Internet browsing, standard-definition DVD viewing, and office applications.
- G33 Express features a reduced-performance GMA X3100 graphics engine, which is close enough to the X3500 to perform similar tasks.
- G31 Express reduces DRAM capacity to 4GB, compared to 8GB for the G33 and G35, and reduces graphics features slightly.
Intel Southbridge for LGA 775
Southbridge compatibility for LGA 775 northbridge components is typically limited by generation.
- ICH10R supports 12 USB 2.0 ports, six PCIe 1.1 lanes, a dedicated pathway for Intel’s gigabit Ethernet MAC, integrated HD audio, six SATA 3.0 Gb/s ports, AHCI, and RAID modes 0, 1, 5, and 10. It mates with Intel 4-series chipsets (P45, G43, etc.), except for the G41 and X48.
- ICH10 removes software RAID modes from ICH10R.
- ICH9R has the features listed above for the ICH10R, but mates with Intel’s 3-series (X38, P35, etc.) chipsets, in addition to the X48 Express, but excluding the G35 Express.
- ICH9 removes software RAID modes from ICH9R.
- ICH8R was developed for Intel’s 965-series chipsets, but carried over into the G35 Express. Its features are similar to those listed for the ICH10R, but with two fewer USB 2.0 ports (10 total).
- ICH8 removes software RAID modes from ICH8R
- ICH7 mates with the G31 northbridge and is limited to six USB 2.0 ports, four PCIe 1.1 lanes, a 10/100 network MAC, and four SATA 3.0 Gb/s ports. It also supports two Ultra ATA 100 drives, although Intel doesn't seem to publicly document this feature.
Nvidia Chipset for LGA 775
Primarily a graphics company, Nvidia has long produced integrated graphics chipsets to boost 3D performance compared to Intel’s integrated offerings, and had also wedged its way into the discrete LGA 775 chipset market by requiring Nvidia chipset components to enable the SLI option of its graphics card drivers.
- nForce 790i Ultra SLI supports 32 PCIe 2.0 lanes through its northbridge, plus 28 PCIe 1.1 lanes from its southbridge, allowing for up to three graphics cards to get a full set of 16 lanes or up to seven eight-lane slots. The chipset officially supports up to FSB-1600 and DDR3 memory speeds up to 2,000 MT/s and even has two gigabit Ethernet controllers built-in. Its SATA controller supports up to six 3.0 Gb/s drives with RAID 0, 1, 0+1, and 5, but provides 10 USB 2.0 ports.
- nForce 790i SLI reduces the 790i Ultra SLI’s official memory support to DDR3-1333, although unsanctioned use of higher-speed modules is possible through the BIOS of most motherboards.
- nForce 780i SLI adds PCIe 2.0 capability to the nForce 680i SLI chipset via an NF200 bridge. It continues the former part’s support for up to FSB-1333 and up to DDR2-800 memory, and higher memory speeds are easily selectable in BIOS. The NF200 bridge supports two graphics cards with 16 PCIe 2.0 lanes, while the chipset’s remaining 28 PCIe 1.1 lanes support an additional x16 graphics card, an x8 card, and six x1 devices. The chipset also supports dual gigabit Ethernet, 10 USB 2.0 ports, six SATA 3.0 Gb/s, and two Ultra ATA 133 drives with the user-configurable options of RAID modes 0, 1, 0+1, and 5.
- nForce 750i SLI adds PCIe 2.0 capability to the nForce 650i SLI via a NF200 bridge that has been further reduced to 16 lanes. In addition to the single and dual graphics cards attached through the NF200, the underlying chipset supports a single gigabit Ethernet interface, eight USB 2.0 ports, and four SATA 3.0 Gb/s drives. Processors up to FSB-1333 and memory data rates up to DDR2-800 are appropriate for this chipset.
- GeForce 9400 mGPU is a significantly higher-clocked version of the earlier 9300 mGPU.
- GeForce 9300 mGPU features a single-component design that supports up to FSB-1333, DDR2-800, and DDR3-1333, 20 lanes of PCIe 2.0 connectivity, a separate pathway for on-chipset gigabit Ethernet control, 12 USB 2.0 ports, six SATA 3.0 Gb/s drives, AHCI, and RAID modes 0, 1, 0+1, and 5. A total of 16 lanes from the PCIe 2.0 controller are dedicated to a single graphics card, and the chipset also allows pairing a low-cost graphics card with the integrated graphics engine for improved performance.
- GeForce 7150 mGPU contains an old and weak graphics engine that, like its G35 competitor, should be reserved for DVD viewing and less graphically-intense tasks. It also supports a PCIe x16 card (using v1.1 transfer mode), 10 USB 2.0 ports, a single integrated gigabit Ethernet port, two Ultra ATA 133 drives, four SATA 6.0 Gb/s ports, and RAID modes 0, 1, 0+1, and 5.
- GeForce 7100 mGPU has an integrated graphics clock that is 5% slower than the 7150, but with otherwise identical features.
- GeForce 7050 mGPU has a 16% slower integrated graphics clock than the 7100 and, depending on the version, it also may be limited to 10/100 networking, eight USB 2.0 ports, and no RAID 5 or 0+1 options.