Editing Northbridge (computing) (section)

{{More citations needed|date=January 2008}}
{{Short description|PC chip handling onboard control tasks}}
[[File:Chipset schematic.svg|thumb|300px|A typical north/southbridge layout (2015)]]
[[File:Motherboard diagram.svg|thumb|300px|A typical north/southbridge layout (2007)]]

In computing, a '''northbridge''' (also '''host bridge''', or '''memory controller hub''') is a [[Integrated circuit|microchip]] that comprises the core logic [[chipset]] architecture on [[motherboard]]s to handle high-performance tasks, especially for older [[personal computer]]s. It is connected directly to a [[CPU]] via the [[front-side bus]] (FSB), and is usually used in conjunction with a slower [[Southbridge (computing)|southbridge]] to manage communication between the [[central processing unit|CPU]] and other parts of the motherboard.<ref>{{cite web|title=Definition of:Northbridge|url=https://www.pcmag.com/encyclopedia/term/48076/northbridge|publisher=PC Magazine|access-date=September 26, 2015}}</ref>

Historically, separation of functions between CPU, northbridge, and southbridge chips was necessary due to the difficulty of integrating all components onto a single [[Die (integrated circuit)|chip die]].<ref>{{cite web |date=2006-01-27 |title=Chipset: Northbridge and Southbridge |url=http://www.rigacci.org/wiki/doku.php/doc/appunti/hardware/chipset |access-date=2015-05-07 |publisher=Rigacci.org}}</ref> However, as CPU speeds increased over time, a [[Von Neumann bottleneck|bottleneck]] emerged due to limitations caused by [[data communication|data transmission]] between the CPU and its support chipset.<ref>{{cite book |last1=Kent |first1=Allen |url=https://books.google.com/books?id=Q_tqLg5buqYC |title=Encyclopedia of computer science and technology |date=1999 |publisher=Dekker |isbn=9780824722937 |location=New York, NY [u.a.] |pages=500 |access-date=September 26, 2015}}</ref> The trend for integrated northbridges began near the end of the 2000s {{Ndash}}for example, the [[List of Nvidia graphics processing units#GeForce 300M .283xxM.29 series|Nvidia GeForce 320M]] GPU in the 2010 MacBook Air was a northbridge/southbridge/GPU combo chip.<ref>[http://digitalgravitas.wordpress.com/2010/10/25/the-macbook-air-a-sign-of-things-to-come/ The Macbook Air: A Sign of Things to Come – Digital Gravitas]</ref>

On older Intel based PCs, the northbridge was also named external '''memory controller hub''' or '''graphics and memory controller hub''' if equipped with integrated graphics. Increasingly these functions became integrated into the CPU chip itself,<ref name="register">{{cite web |title=Trustworthy x86 laptops? There is a way, says system-level security ace |url=https://www.theregister.co.uk/2015/12/31/rutkowska_talks_on_intel_x86_security_issues/ |access-date=January 4, 2016 |publisher=The Register}}</ref> beginning with memory and graphics controllers. Since the 2010s, [[die shrink]] and improved [[transistor density]] have allowed for increasing chipset integration, and the functions performed by northbridges are now often incorporated into other components such as southbridges or CPUs themselves.<ref name="register" /><ref name="hope">{{cite web|website=Computer Hope|date=October 7, 2019|title=Northbridge|url=https://www.computerhope.com/jargon/n/northbri.htm}}</ref>

[[Intel]] and [[AMD]] have both released chipsets in which all northbridge functions had been integrated into the CPU.<ref name="hope" /> The corresponding southbridge was renamed by Intel as the [[Platform Controller Hub]] and by AMD as the [[Fusion controller hub]]. AMD FX CPUs continued to require external northbridge and southbridge chips. Modern Intel Core processors have the northbridge integrated on the CPU die, where it is known as the [[uncore|uncore or system agent]].