The IGP Chronicles Part 1: Intel's G45 & Motherboard Roundupby Anand Lal Shimpi & Gary Key on September 24, 2008 12:00 PM EST
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The GMCH/ICH Showdown: What's New in the 4-Series
The role of the chipset in a modern PC has changed considerably over the years, mostly due to AMD's integration of the main memory controller onto its CPU die. Intel won't do the same until Nehalem, so the role of its chipsets remain relatively unchanged despite taking on additional functionality over the years.
The role of a chipset is to connect everything in your system to one another; it's the controller logic that connects your CPU to your graphics card, Ethernet, hard drives, USB peripherals, etc.., and connects all of them to main memory. For all of modern desktop chipset history, most chipsets have been two chip solutions - normally known as a North and South Bridge. The North Bridge generally housed the memory controller and AGP or PCI Express interface, while the South Bridge took care of less bandwidth intensive things like PATA/SATA ports, LAN, USB, sound, etc...
Intel came up with its own terms for North and South Bridge back in the late 1990s with a move to its "hub architecture". The North Bridge became the Graphics and Memory Controller Hub (GMCH) while the South Bridge became the I/O Controller Hub (ICH). The GMCH is technically only present when it's a chipset with integrated graphics, otherwise it's simply a MCH.
The 4-series GMCH, which is used in the G45 chipset as well as the P45 chipset (just a MCH there) is honestly not much different from the 3-series (G)MCH used in the G35/P35 chipsets:
|4-series GMCH||3-series GMCH|
|FSB||800 / 1066 / 1333MHz||800 / 1066 / 1333MHz|
|Memory Controller||2 x 64-bit DDR2/DDR3 channels||2 x 64-bit DDR2/DDR3 channels|
|Memory Speeds Supported||DDR2-800/667 |
|PCI Express||16 PCIe 2.0 lanes||16 PCIe 1.1 lanes|
|Graphics||GMA X4500|| |
|Shader Processors||10|| |
|Full H.264/VC-1/MPEG-2 HW Decode||Yes||No|
The pinout is different, thus requiring new motherboard designs but the performance characteristics of the two GMCHs are basically identical. The 4-series chipsets added PCIe 2.0, but the biggest performance impact is the improved graphics core in the 4-series GMCH. If you've got a 3-series motherboard today, the 4-series equivalent shouldn't be any faster in non-gaming/video decoding applications (although it will use less power thanks to the 65nm manufacturing process).
The ICH comparison is even more tame, there's honestly no change between ICH10 and its predecessor: ICH9.
|PCI Express||6 x1 PCIe 1.1||6 x1 PCIe 1.1||6 x1 PCIe 1.1|
|USB||12 ports||12 ports||10 ports|
|SATA (300MB/s)||6 ports||4 ports (ICH9 base) |
6 ports (ICH9R)
|4 ports (ICH8 base) |
6 ports (ICH8R)
|RAID*||RAID 0/1/5/10||RAID 0/1/5/10||RAID 0/1/5/10|
|HD Audio Interface||Yes||Yes||Yes|
|Ethernet||Intel Gigabit LAN||Intel Gigabit LAN||Intel Gigabit LAN|
|G/MCH Interface||DMI 10Gb/s each direction, full duplex||DMI 10Gb/s each direction, full duplex||DMI 10Gb/s each direction, full duplex|
Even going back to ICH8, there's hardly a difference here (you do get some more USB ports with ICH9/10). There are some minor differences, for example the base ICH10 features 6 SATA ports while the base ICH8/9 only featured 4. The take away point is that feature-wise, there's not much new.