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
.