Editing Northbridge (computing) (section)

==Overview==
The northbridge typically handles communications among the [[Central processing unit|CPU]], in some cases [[Random-access memory|RAM]], and [[PCI Express]] (or [[Accelerated Graphics Port|AGP]]) video cards, and the [[southbridge (computing)|southbridge]].<ref>{{cite web|last=Jones |first=George |url=http://www.informit.com/articles/article.aspx?p=339936 |title=Motherboards & Core-Logic Chipsets: The Deep Stuff &#124; What the North Bridge and South Bridge Do |publisher=InformIT.com |date=2004-10-22 |access-date=2015-05-07}}</ref><ref>George Jones - Maximum PC 2005 Buyer's Guide - Prentice Hall PTR - {{ISBN|0-7686-6312-1}}</ref> Some northbridges also contain integrated video controllers, also known as a '''Graphics and Memory Controller Hub''' in Intel systems. Because different processors and RAM require different signaling, a given northbridge will typically work with only one or two classes of CPUs and generally only one type of RAM.

There are a few chipsets that support two types of RAM; generally, these are made available when there is a shift to a new standard. For example, the northbridge from the 2002 [[Nvidia]] [[nForce2]] chipset only worked with [[Socket A]] processors combined with [[DDR SDRAM]].

{{Citation needed span|The [[Intel]] i875 chipset will only work with systems using [[Pentium 4]] processors or [[Celeron]] processors that have a clock speed greater than 1.3&nbsp;GHz and utilize DDR SDRAM, and the Intel i915G chipset only works with the Intel Pentium 4 and the Celeron, but it can use DDR or [[DDR2 SDRAM|DDR2]] memory.|date=January 2022}}

=== PowerPC ===
Northbridge chips are most commonly found on X86-based PCs, but they can also be found on other platforms, such as the [[PowerPC]] platform. A common example of a northbridge on a PowerPC platform is in Apple's older PowerPC-based computers like the [[iMac G5]], which utilized an IBM CPC945 Northbridge chip. According to an Apple Developer note, The [[Power Mac G5]]'s northbridge chip connected to a "Mid Bridge", which then connected to a south bridge.<ref>{{Cite web|url=https://developer.apple.com/library/archive/documentation/Hardware/Conceptual/PowerMac_G5_05Oct/Articles/PwrMacG5-0510_archi.html|title=Power Mac G5 Developer Note}}</ref>

[[File:IBM CPC945 Northbridge (15420568058).jpg|thumb|right|A Kodiak chip: an implementation of IBM's CPC945 northbridge in an [[iMac G5]], a PowerPC-architecture system.]]