PC hardware--CPU & Motherboard & RAM/Chipset


QUESTION: I was looking at the specs for my system and I have a 2ND GEN. i3-2130 CPU.

The Chipset is intel B75 Express but I do not know if this is my Northbridge or Southbridge.

Then I see my DMi speed is up to 20Gbps both ways full Duplex.

I know DMi is the link between the Northbridge and Southbridge.
So when they give my my DMi speed is this my Northbridge speed? You know my FrontSide BUS?


ANSWER: Hello Bob. You are correct to identify the DMi (Direct Media interface) as the link between the Northbridge and Southbridge.

The FSB, (Front Side Bus), is essentially the data bus between the CPU and Northbridge for connectivity to RAM and everything else. Nowadays the memory controller is directly in the CPU and therefore allows for faster CPU to memory data flow. The CPU is still connected to a Northbridge to this day, with the exception of the RAM data. The Northbridge still performs high speed data bus operations for the ever upgrading demands of the PCI Express slots.

The SouthBridge is also being faded out with some of Intels newer boards where the devices originally connected through the Southbridge are now being directly connected to the Northbridge to again cut out the middle man for higher bandwidth data flow to the CPU.

Also, Chipset is in simple definition a "set of chips". The Northbridge AND Southbridge are the main chips in the definition. The 20Gb/s speed rated by the DMi is between the Northbridge and Southbridge. The FSB is rated by the processor.

Hope this helps, have a great day!

---------- FOLLOW-UP ----------

QUESTION: Ok so the 20Gbps my DMi has is the Data speed between my Northbridge and Southbridge only I get this.

So if I want to know what my FrontSide BUS Speed is I look up my CPU the
i3-2130 2nd Generation.

But this will tell me what my CPU can go at for FrontSide BUS but it does not meen my Motherboard is going at this speed?

My CPU may be able to go at a FrontSide BUS speed but maybe my Motherboard is going slower.

Or am I not thinkiong ion the right way?

The best way for me to explain how to determine how to determine the speed of the FSB is to simply link you the article from Wikipedia. Article is here: http://en.wikipedia.org/wiki/Front-side_bus .

It explains much more than you may be asking for, but in short, "The bandwidth or maximum theoretical throughput of the front-side bus is determined by the product of the width of its data path, its clock frequency (cycles per second) and the number of data transfers it performs per clock cycle. For example, a 64-bit (8-byte) wide FSB operating at a frequency of 100 MHz that performs 4 transfers per cycle has a bandwidth of 3200 megabytes per second (MB/s):

   8 Bytes (64 bit bus width) 100 MHz 4/cycle = 3200 MB/s"

As I mentioned before in my last answer, the FSB is a dying term as memory is directly connected to the CPU via AMD's Hyper Transport or Intels equivalent name. The FSB is still there, but its bandwidth is freed up to just data from the Northbridge/Southbridge data since RAM data is no longer passed through like it has before.

Hope this helps, Have a great day!

PC hardware--CPU & Motherboard & RAM

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I can answer most No POST problems, compatibility between parts, upgrade options, troubleshooting, etc. Before you ask me a question, please do some research. I do not give PC speed reviews for video games.


Many, many years of experience working with the hardware components of many types of computers including desktops, laptops, kiosk computers, and even running Windows 3.1, 95, and 98 on the PSP (Sony PlayStation Portable). I've replaced capacitors on desktop motherboards making them working like new again with a high success rate. This is my hobby/job every day.

Associates of Science in Computer Information Technology

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