What is the south and north bridge of a computer. What is the north and south bridge in a computer

South bridge failure is the most common problem on boards using i845/i865/i848 series chipsets. The main reason is the burnout of the USB controller built directly into the south bridge. However, the purpose of this article is not to search for reasons, but to find ways to “bring back to life” such boards.

In the event of a failure due to the “dying” of the USB controller (in the south bridge), the following main options for the behavior of the motherboard are possible:
1. The board does not turn on (forced start gives zeros on the postcard), the south bridge is already heating up from the standby power supply. The board starts, but freezes at POST code 25 (for Award BIOS 6.0) or D0 (for AMIBIOS8).
2.The board starts, but freezes at POST code 25 (for Award BIOS 6.0) or D0 (for AMIBIOS8).
Solution methods:

1. Restoration using the "annealing" method
The first case is especially typical for Asus P4P800 series boards. With this option, you can and should use the “annealing” method. What does "annealing" mean? This means that in order to prevent shortening of the power supply to already burnt out parts (inside the south bridge), a deliberately “burning” voltage is supplied to them until they finally burn out, thus ceasing to interfere with the functioning of all the others, which, as a rule, remain perfectly serviceable , blocks inside the chip.
"Annealing" of standby power supply
We check whether the duty 5V and 3.3V are sagging.
We supply standby power and check whether the standby 5V and 3.3V are sagging. If yes, we supply “power” 5V/3.3V to them and briefly turn on the power supply (with a jumper on PS_ON). We remove all jumpers and check the control voltages. “We got up” - good, if we didn’t get up - we try again, and several more times, it doesn’t work - we leave the “power” jumpers and move on.
"Annealing" the load of capacitors connected to the outputs of internal standby sources
We look for three capacitors on the board connected to the outputs of internal standby 1.5V sources (VCCSUS1_5A,B,C) - at least one of them has dropped to 0.2..0.4V (as a rule, this is only VCCSUS1_5A) and “anneal” its load. To do this, we first supply 1.5V (possibly from Vcc of the installed processor, or from Vmch/agp). If this does not help, we make several short-term short circuits to 2.5V memory power supply or, in extreme cases, 3.3V. It is dangerous to burn out five volts - there is a possibility that the south bridge will die for good. If 2.5V does not help, before applying 3.3, it is recommended to try 3.3VSB first (as a relatively low-current source). If as a result the voltage rises to the required 1.5V, then the operation was successful! (The temperature of the south bridge should decrease by 15-20 degrees compared to what it was before the “annealing”).

2. Recovery by flashing the BIOS
The second case is typical for Gigabyte 8IPE1000 series motherboards. In this case, in general, it may be enough just to flash the “correct” BIOS.
Using ProBIOS
To check for the possibility of reviving boards with such a problem (stopping at the 25th postcode for Avard and D0 for AMI), you can and should use a “probios” (tested bios). ProBIOS is a special BIOS suitable for most motherboards based on i845/i865/i848 + ICH4/ICH5 logic. It contains initialization of only “vital” parts of the board (which allows it to be used as a test and for all “other” cases - just repairs), including skipping the procedure in which in “standard” (ordinary, “native”) BIOS board freezes.

So, as a result, we should get a reduction in the heating of the south bridge (by 15-20 degrees compared to the temperature before the “treatment”), as well as a fully functional motherboard. True, adjusted for the missing USB ports, but nothing will prevent you from installing an “external” PCI USB controller and thus getting a completely working system.

Laptops and personal computers are very complex devices. There are so many microchips in them that an untrained user could never have dreamed of. Often, all these “pieces of hardware” tend to fail. In service centers they get off with the faceless wording “the north bridge of the motherboard has burned out.” And what kind of bridge this is and where it came from on this very board - God knows. Severe IT specialists are not going to explain the structure of a computer to mere mortals. But you need to know this, since the problem is very serious and occurs quite often. This is what we will talk about now.

What is northbridge

The north bridge is a controller on the motherboard that is responsible for the operation of some of its very important components. Often this bridge is paired with an integrated graphics core (especially in laptops). This is not surprising, because the bridge is responsible for the operation of the video adapter, central processor, RAM and other particularly important components of the computer. It is by His grace that the entire multi-component system works. It is named so because of its location. But not because of the temperature.

It’s a paradox, but much “colder” than the northern one. This is due to the fact that the northbridge is in close proximity to the processor and video card. This affects his temperature in the most negative way. That’s why it is equipped with an additional cooler or cooling radiator. In addition, this bridge is usually installed in the upper part of the body. And hot air, as you know, rises. Hence the additional load on this element. Is it worth mentioning that this particular component of the motherboard burns out first?

Signs of failure

It's pretty simple. Since the north bridge of a laptop or PC is responsible for the operation of the most important components, it is quite easy to diagnose its failure. Just turn on the computer. The first sign will be that there will be no image on the screen. There may also be no access to the hard drive. The RAM won't boot either. As a result, you will hear a characteristic sound signal in the form of a nasty squeak.

Another symptom may be a cyclic reboot of the computer. It all depends on the degree of damage to the component. Another common symptom may be that the computer turns on after the fifth or even tenth time. If such symptoms occur, then your northbridge on your laptop or PC is seriously damaged. And you shouldn’t delay this, because you can lose all the other components of the computer that are still working properly.

Causes of failure

There are a great many of them. Therefore, it is impossible to immediately understand what happened. The most common reason is overheating. The North Bridge simply burns out due to exceeding the permissible temperature. This kind of thing occurs when the component is not cooled sufficiently. Physical damage from impact is also possible. Moreover, it is not necessary to “pound” the motherboard itself. The controller is very fragile. A little push is enough for him. The last reason is a manufacturing defect. It is extremely rare. Manufacturers usually warn users that the motherboard contains a chip with a flaw. It's a matter of time when it flies off.

The north and south bridge are quite finicky components. All they need is a slight shake, a minor overheat or a power surge - and that’s it, they’re dead. By the way, liquid getting inside the computer is also a common cause of failure. Enough for the smallest drop to hit the contact, a short circuit immediately occurs and the controller burns out. And without this control element, PC operation is impossible.

Repair

You won't be able to repair a faulty north bridge with your own hands. This is a complex device that is produced by specialized robots. Such precision is inaccessible to humans. Therefore, in service centers no one will tinker with the controller. There is only one way out - to replace the bridge. The quality of the replacement depends on the specific master. It is not recommended to give your laptops and PCs to the hands of “traditional craftsmen”, because these comrades can kill everything there. It is better to use the services of professionals.

If you have a motherboard with a obviously faulty controller (which has been confirmed by the manufacturer), then it is better not to wait at all for hour X. The North Bridge will be replaced under warranty completely free of charge at the manufacturer’s authorized service center. But it’s better not to delay this, because the consequences can be very sad.

Prevention

In order to avoid failure of this component of the motherboard, you just need to follow not very complicated operating rules. Firstly, you need to regularly clean the case from dust and dirt. Particular attention should be paid to coolers and other components of the cooling system. Because if you leave everything to chance, the north bridge will simply burn out, unable to withstand the high temperature. Also, you should always check the cooling system for functionality. If any cooler fails, it should be replaced immediately.

Secondly, never expose your laptop or PC to physical impact. This also has a detrimental effect on this component. Thirdly, keep pets away from laptops and PCs. Their fur very quickly clogs the cooling system. The result is overheating and failure of the bridge. Fourth, never drink anything near a laptop or PC. One drop of liquid leaking onto the motherboard is enough for the north bridge to “play into the box”.

Conclusion

Now you know what the north bridge of a computer motherboard is, what it serves and what it is afraid of. Following simple rules for safe computer operation will help avoid failure of this finicky component. Diagnosing a malfunction of this component of the motherboard is also very simple. If the PC does not start, reboots and there is no image, then with a high degree of probability we can say that the north bridge has died. It is impossible to repair it - only change it. However, it is easier to replace it than the entire motherboard. Treat your computer with care, and you will never have such problems.

Let's talk about motherboard controllers. In particular, we will examine the question of what the north and south bridges are. The average computer user is unlikely to have ever encountered such a term. However, if this very ordinary user, after a PC breakdown, took it to be “torn to pieces” at a service center, sometimes he may receive a simple answer: “The South Bridge burned down, it cannot be restored!” The answer is reassuring, you need to buy a new motherboard. So that’s how it is, replacing the south bridge is really a thankless task, and maybe even unrealistic. But people, as a rule, do not know what the concepts of north or south bridge mean.

The north and south bridges of the computer (or, more correctly, the motherboard) are two main functional controllers that are responsible for the operation of all components of the motherboard and are called a chipset. Let's look at them separately. You can read more about the north and south bridges. Let's start with the north bridge.

Northbridge is a system controller, which is one of the elements of the motherboard chipset, responsible for working with random access memory (RAM), video adapter and processor (CPU). The north bridge is responsible for the system bus frequency, the type of RAM and its maximum possible size. One of the main functions of the north bridge is to ensure interaction between the motherboard and the processor, as well as determine the operating speed. Part of the northbridge in many modern motherboards is the built-in video adapter. Thus, the functional feature of the north bridge is also the control of the video adapter bus and its speed. The north bridge also provides communication between all of the above devices and the south bridge.

The Northbridge gets its name from its “geographical” location on the motherboard. Externally, it is a square-shaped microchip located under the processor, but on the top of the motherboard. Typically, the northbridge uses additional cooling. Usually this is a passive radiator, less often - a radiator with active cooling in the form of a small cooler. This is due to the fact that the temperature of the north bridge is always about 30 degrees Celsius higher than the temperature of its “southern brother”.

The elevated temperature is quite justified. Firstly, the north bridge is located in close proximity to the central processor, and secondly, it is located above the video card, hard drives and south bridge. This means that some of the heat from the above devices reaches the northbridge. And thirdly, the most important thing is that the north bridge is responsible for processing commands from the most powerful components of the system - the processor, memory and graphics. Therefore, we will assume that an increased temperature rating is the norm for the north bridge of any motherboard.

South Bridge

The Southbridge is a functional controller known as an input/output controller or ICH (In/Out Controller Hub). Responsible for the so-called “slow” operations, which include working out the interaction between the IDE, SATA, USB, LAN, Embeded Audio interfaces and the system north bridge, which, in turn, is directly connected to the processor and other important components, such as RAM or video subsystem. The south bridge is also responsible for processing data on PCI, PCIe and ISA buses (in older motherboard models).

The list of motherboard systems supported by the south bridge is quite large. In addition to the above IDE, SATA, USB, LAN and other things, the south bridge is also responsible for the SM bus (used to control fans on the board), DMA controller, IRQ controller, system clock, BIOS, APM and ACPI power supply systems, LPC bus Bridge.

As a rule, the failure of the south bridge puts an end to the life of the motherboard. It is the south bridge that is sometimes the first shield to take the blow. Due to technological features, this is so. The reasons for the “death” of the south bridge are an order of magnitude greater than those of the north bridge, because it works directly with “external” devices. Thus, a common cause of YUM failure is simple overheating caused by a short circuit, for example, in a USB connector. Or there is a power failure on the hard drive. Because In most cases, the southbridge is not equipped with an additional cooling system; it overheats and burns out. Less commonly, the reason for the breakdown of the south bridge is a manufacturing defect. Deformation (excessive bending) of the system board also leads to increased heating of the south bridge with subsequent failure.

To extend the life of the south bridge, you can install homemade cooling. A simple passive heatsink with hot melt adhesive can extend the life of your motherboard in case of overheating symptoms. It is not easy to detect such a symptom. Not all motherboards are equipped with thermal sensors in the north and south bridges of the system board. Recently, to solve the problem of south bridges, some motherboard manufacturers began to equip these chips with additional passive cooling and a temperature sensor, which, if something happens, will notify the user about the problem. Note, however, that under normal conditions there is no reason for increased heating of the south bridge, but remember that the south bridge is responsible for many devices that could contribute to its overheating and combustion. Be careful.

Sometimes situations arise when your computer stops working and you have to take it to a service center. In some cases, you can hear that the South Bridge is faulty and the entire motherboard needs to be replaced. The diagnosis seems to be clear, but not every user knows the concepts of South Bridge and North Bridge. These two computer devices, or rather the motherboard, are the main functional controllers responsible for the operation of all other components of the motherboard. Together, these bridges form a chipset, but still each of them is responsible for its own functions. These square-shaped chips received such an unusual name due to their location on the motherboard: North - in the upper part under the processor, and South - in the bottom.

North Bridge

The north bridge is a control device that is responsible for the interaction of the motherboard with your computer's RAM, video card and processor. In addition, this chipset element not only interacts, but also controls the speed of operation of the components described above. One of the parts of the Northbridge is the built-in video adapter found in some modern motherboards - the so-called integrated video card. Accordingly, this bridge additionally controls the bus of the device responsible for transmitting the image to the monitor and its speed. Additionally, the North Bridge connects all mentioned devices to the South Bridge. As a rule, this chip has its own passive cooling, that is, a radiator is installed; less often you can find active cooling using a cooler. This is done because the temperature of the North Bridge is about 30 degrees higher than the temperature of its South Bridge. This is due to the processing of commands from the most active components of the system and the close proximity to the processor, due to which heating occurs from the outside.

South Bridge

The South Bridge is a functional controller, the main function of which is to implement the so-called “slow” connections, which include various buses, USB, SATA and LAN controllers, power supply system, BIOS and even the clock, in general, the list is quite large. That is why the failure of the South Bridge leads to the need to replace the entire motherboard. Considering that this controller interacts directly with external devices, the cause of a breakdown may be ordinary overheating, caused, for example, by a short circuit.