What is north/south bridge on motherboard

[Carlos1010]

Hi all,

Recently I have looked on motherboard pictures and I saw this thing called the north and south bridges, does anyone know what these things are and what are they used for. Thanks in advanced! 

[Samppa221]

 

 

[Sakkura]

The northbridge is what connects the CPU to the memory, and to the directly attached PCIe lanes (usually to the graphics card), as well as to the southbridge.

 

The southbridge connects to all the other IO stuff - network, USB, SATA, additional PCIe slots etc.

 

Nowadays the northbridge is usually integrated into the CPU and isn't a separate chip on the motherboard.

[Carlos1010]

Just now, Sakkura said:

The northbridge is what connects the CPU to the memory, and to the directly attached PCIe lanes (usually to the graphics card), as well as to the southbridge.

 

The southbridge connects to all the other IO stuff - network, USB, SATA, additional PCIe slots etc.

 

Nowadays the northbridge is usually integrated into the CPU and isn't a separate chip on the motherboard.

So is it like the center of communication, the thing that connects other components together? 

[Oshino Shinobu]

On modern Intel boards, the primary functions of the Northbridge are integrated into the CPU, with the remaining Northbridge functions and Southbridge functions being combined in the PCH. I'd expect Northbridge/Southbridge to be completely a thing of the past once Zen releases (assuming they take a similar approach to Intel). 

[manikyath]

in the olden days (things are changing now, the classic "north bridge" is implemented into the cpu itself on modern intel chips) this was basicly how it worked.

[Carlos1010]

Just now, Oshino Shinobu said:

On modern Intel boards, the primary functions of the Northbridge are integrated into the CPU, with the remaining Northbridge functions and Southbridge functions being combined in the PCH. I'd expect Northbridge/Southbridge to be completely a thing of the past once Zen releases (assuming they take a similar approach to Intel). 

So are you saying that in the future there won't be any north nor south bridges on the motherboard? So do you mean that all the components will link together without the help of a bridge? 

[Oshino Shinobu]

2 minutes ago, Carlos1010 said:

So is it like the center of communication, the thing that connects other components together? 

Yes. The Northbridge connects the CPU to various motherboard functions, The Southbridge deals with less important functions and is connected to the CPU via the Northbridge. 

 

Both are redundant on modern Intel boards due to being replaced by CPU integration and the PCH. 

[Oshino Shinobu]

2 minutes ago, Carlos1010 said:

So are you saying that in the future there won't be any north nor south bridges on the motherboard? So do you mean that all the components will link together without the help of a bridge? 

On modern Intel boards, they've already been removed, or more accurately, restructured and relocated. Right now, the most recent boards that use NB/SB (AFAIK) are AM3+ boards which are outdated anyway. 

 

New systems with them being integrated into other components and grouped with other functions (PCH, for example) is much more efficient. They are still connected, but they're not individual chips on the board anymore. 

[manikyath]

Just now, Carlos1010 said:

So are you saying that in the future there won't be any north nor south bridges on the motherboard? So do you mean that all the components will link together without the help of a bridge? 

the idea of a north bridge / south bridge is that it's a "sensible" way to spread the work over different pieces of silicon.

 

on the modern intel parts, stuff's a bit more complex, but basicly then cpu itself does the numbercrunching, the north bridge (on modern intel parts integrated in the cpu) handles the high bandwidth communications like to the ram, to the pci-e devices (which usually need a lot of bandwidth to work efficiently) and anything that is not "high bandwidth" (legacy slots, usb, etc) gets "dumbly" passed trough to the south bridge (on modern intel boards this is basicly the "chipset") which further handles the communication to USB, legacy, sata, on-board devices like audio and network connectivity, and so on.

[Carlos1010]

7 minutes ago, manikyath said:

the idea of a north bridge / south bridge is that it's a "sensible" way to spread the work over different pieces of silicon.

 

on the modern intel parts, stuff's a bit more complex, but basicly then cpu itself does the numbercrunching, the north bridge (on modern intel parts integrated in the cpu) handles the high bandwidth communications like to the ram, to the pci-e devices (which usually need a lot of bandwidth to work efficiently) and anything that is not "high bandwidth" (legacy slots, usb, etc) gets "dumbly" passed trough to the south bridge (on modern intel boards this is basicly the "chipset") which further handles the communication to USB, legacy, sata, on-board devices like audio and network connectivity, and so on.

Why do we even need these bridges? Why can't every part do their own job?

[Carlos1010]

9 minutes ago, Oshino Shinobu said:

On modern Intel boards, they've already been removed, or more accurately, restructured and relocated. Right now, the most recent boards that use NB/SB (AFAIK) are AM3+ boards which are outdated anyway. 

 

New systems with them being integrated into other components and grouped with other functions (PCH, for example) is much more efficient. They are still connected, but they're not individual chips on the board anymore. 

So when you said that the north bridge has already been removed, how do you know which CPU can do the numbercruching of all the components and which ones can't? Or is it based on the motherboard? For example can the i7 6700k resist at doing this? Also thanks for your response!

[manikyath]

Just now, Carlos1010 said:

Why do we even need these bridges? Why can't every part do their own job?

the bridges are doing "their own job"

 

they handle the communication between the different pieces of hardware, in a way where the faster communication doesnt get bogged down by the slower communication.

 

for ex. the north bridge doesnt need to bother figuring out if data is for USB, sata, legacy, or w/e else, it just passes it trough to the next piece of silicon, so the north bridge can do more important thins like passing data between your cpu and gpu.

 

the north and south bridge are basicly traffic lights that guide cars in the direction they need to go while avoiding crashes, and avoiding traffic jams from everyone doing whatever they feel like.

[Sakkura]

34 minutes ago, Oshino Shinobu said:

Yes. The Northbridge connects the CPU to various motherboard functions, The Southbridge deals with less important functions and is connected to the CPU via the Northbridge. 

 

Both are redundant on modern Intel boards due to being replaced by CPU integration and the PCH. 

The PCH is basically just a new name for the Southbridge, though a few functions have been shuffled around.

[Oshino Shinobu]

Just now, Sakkura said:

The PCH is basically just a new name for the Southbridge, though a few functions have been shuffled around.

The Southbridge is in there, but it's basically just a combination of functions. There are some functions that the Northbridge used to perform that were put into the PCH as well, along with all the Southbridge functions.