Difference between cpu, processor and core?

[linuxque]

Hi,
Unable to understand the difference between cpu, core, processor.
If cpu consists of Alu, Memory unit and I/O, then
a) What is a processor? What does it contains?
b) Does or Can the cpu contain multiple processors?
c) What is a core?

When we say a 8 CPU Server, the extended infomation says it has 8 cores. If both are same, then what's the difference between core and cpu?

The more I read on these topics, the more I am getting confused?

Thanks
Linuxque

 

[hairystuff]

THIS... IS.. HOMEWOOOOOOORRRRRKKKK!!!!

 

[Flying-Q]

Hi,
Unable to understand the difference between cpu, core, processor.
If cpu consists of Alu, Memory unit and I/O, then
a) What is a processor? What does it contains?
b) Does or Can the cpu contain multiple processors?
c) What is a core?

When we say a 8 CPU Server, the extended infomation says it has 8 cores. If both are same, then what's the difference between core and cpu?

The more I read on these topics, the more I am getting confused?

Thanks
Linuxque

This should give you a good start

Wikipedia entry for CPU design

enjoy

Q

 

[Pinhedd]

THIS... IS.. HOMEWOOOOOOORRRRRKKKK!!!!

There's no rule against helping with homework. If someone's confused and asks nicely then that's fine.

To the OP:

The terms 'Processor', 'Core', and 'CPU' are all poorly defined and have undergone many changes in meaning over the year as computer architectures have evolved and changed.

Under modern terminology, 'Processor' and 'CPU' mean more or less exactly the same thing. It would be more accurate to refer to the 'processor package' because there's no real standard to what a the package contains. Very old CPUs from 15-20 years ago contained little more than the bare minimum to execute tasks.

They contained the ALUs, fetch and decode hardware, Instruction pipeline, Interrupt handling hardware, some IO control hardware and that's about it. After this, cache memory was added to the CPU to improve execution

Then, the execution parts of the processor were duplicated. The ALUs, fetch and decode, instruction pipline, and some cache memory were organized into what we now call "cores". Each core is capable of functioning on its own and contain all the resources necessary to perform computational tasks that do not involve interacting with components outside the CPU. IO Control, interrupt handling, etc... were all shared between all the cores.

More recently the memory controller itself has been moved into the CPU package. It sits along side the CPU cores but it is not part of them. Thus it is part of the package, or part of the processor/CPU but it is not part of the 'cores'. Intel used to specifically refer to this as the 'un-core'.

This gets even more complicated when we talk about systems which have multiple physical processor packages installed. Many server and workstation platforms can have 2, 4, or even more processor packages installed. Each processor package contains the same hardware.

Thus, the number of 'cores' in a machine can be computed by taking the number of cores per package and multiplying it by the number of packages in the system. A computer which has two quad core processors has the same number of cores as a computer which has a single octal core processor.

Here is an image of a motherboard that has 4 processor sockets

http://i1-news.softpedia-static.com/images/news2/Tyan-Intros-New-Quad-Socket-AMD-Motherboard-and-Server-Barebone-Supporting-Up-to-512GB-RAM-2.jpg

Each one of those processor sockets (the flat ones with all the pins and metal coverings) can hold an AMD Opteron 6100 series processor. Each Opteron 6100 processor has either 8 or 12 cores inside which means that particular system can have between 8 (a single 8-core processor installed) and 48 cores present (4 12-core processors installed).

 

[linuxque]

THIS... IS.. HOMEWOOOOOOORRRRRKKKK!!!!

hairystuff: Certainly not. I have crossed the age of doing homework!

 

[linuxque]

There's no rule against helping with homework. If someone's confused and asks nicely then that's fine.

To the OP:

The terms 'Processor', 'Core', and 'CPU' are all poorly defined and have undergone many changes in meaning over the year as computer architectures have evolved and changed.

Under modern terminology, 'Processor' and 'CPU' mean more or less exactly the same thing. It would be more accurate to refer to the 'processor package' because there's no real standard to what a the package contains. Very old CPUs from 15-20 years ago contained little more than the bare minimum to execute tasks.

They contained the ALUs, fetch and decode hardware, Instruction pipeline, Interrupt handling hardware, some IO control hardware and that's about it. After this, cache memory was added to the CPU to improve execution

Then, the execution parts of the processor were duplicated. The ALUs, fetch and decode, instruction pipline, and some cache memory were organized into what we now call "cores". Each core is capable of functioning on its own and contain all the resources necessary to perform computational tasks that do not involve interacting with components outside the CPU. IO Control, interrupt handling, etc... were all shared between all the cores.

More recently the memory controller itself has been moved into the CPU package. It sits along side the CPU cores but it is not part of them. Thus it is part of the package, or part of the processor/CPU but it is not part of the 'cores'. Intel used to specifically refer to this as the 'un-core'.

This gets even more complicated when we talk about systems which have multiple physical processor packages installed. Many server and workstation platforms can have 2, 4, or even more processor packages installed. Each processor package contains the same hardware.

Thus, the number of 'cores' in a machine can be computed by taking the number of cores per package and multiplying it by the number of packages in the system. A computer which has two quad core processors has the same number of cores as a computer which has a single octal core processor.

Here is an image of a motherboard that has 4 processor sockets

http://i1-news.softpedia-static.com/images/news2/Tyan-Intros-New-Quad-Socket-AMD-Motherboard-and-Server-Barebone-Supporting-Up-to-512GB-RAM-2.jpg

Each one of those processor sockets (the flat ones with all the pins and metal coverings) can hold an AMD Opteron 6100 series processor. Each Opteron 6100 processor has either 8 or 12 cores inside which means that particular system can have between 8 (a single 8-core processor installed) and 48 cores present (4 12-core processors installed).

@Pinhedd: Thanks a ton! That certainly helps..

 

[Pinhedd]

@Pinhedd: Thanks a ton! That certainly helps..

I got a bit caught up in my own explanation there. I'll try to simplify it a bit since my own definitions were a bit technical.

In simpler terms,

Core: Cores are what handle the arbitrary mathematical and logical workloads. They take high level machine instructions (x86, ARM, MIPS, etc...) and 'decode' them into physical circuit operations. Many other parts of the system, such as GPUs and chipsets operate in a similar manner but are designed with specific purposes in mind which makes them more efficient at these particular tasks. CPU cores are designed with a general purpose, making them jacks of all trades.

Processor / CPU: The combination of one or more 'cores' with supporting hardware and shared resources.

Processor package: The physical casing in which one or more processors or CPUs is contained. The pinout from the package is what allows the processor to interface with the rest of the system. Some processor packages may contain more than one processor die inside of them, or may have the cores and shared resources on separate pieces. The contents of the processor package and how it is organized are up to the manufacturer, hence the distinction between Processor and Processor Package.

For example, the Core 2 Quad processors were actually two individual Core 2 Duo processors in the same package with some very simple supporting hardware to allow them to work together. This stands in contrast to the more modern Sandybridge processors which have all 4 cores and supporting hardware on one chip, a far more efficient design.

 

[hairystuff]

hairystuff: Certainly not. I have crossed the age of doing homework!

There are people in their 90's that have done university and college degrees.

 

[Goden]

There are people in their 90's that have done university and college degrees.

I don't think a university or college would be asking the difference between CPU and Core...

 

[hairystuff]

Why wouldn't they, I've seen questions about dos memory tables and colour bit depths.

 

[linuxque]

Best answer selected by linuxque.

 

[Devaraju]

processor is nothing but CPU both are some.
core is there inside a processor/CPU.Number of cores depends on your processor example 2 cores in dual core processor like this you have quad core octa core etc.....
cpu contains alu,memory controller,register,cu etc..

 

[Devaraju]

processor is nothing but CPU both are some.
core is there inside a processor/CPU.Number of cores depends on your processor example 2 cores in dual core processor like this you have quad core octa core etc.....
cpu contains alu,memory controller,register,cu etc.

 

[Afzalshareef]

Excellent explanation given by Pinhedd ..
Thank you so much ..

THIS... IS.. HOMEWOOOOOOORRRRRKKKK!!!!

There's no rule against helping with homework. If someone's confused and asks nicely then that's fine.

To the OP:

The terms 'Processor', 'Core', and 'CPU' are all poorly defined and have undergone many changes in meaning over the year as computer architectures have evolved and changed.

Under modern terminology, 'Processor' and 'CPU' mean more or less exactly the same thing. It would be more accurate to refer to the 'processor package' because there's no real standard to what a the package contains. Very old CPUs from 15-20 years ago contained little more than the bare minimum to execute tasks.

They contained the ALUs, fetch and decode hardware, Instruction pipeline, Interrupt handling hardware, some IO control hardware and that's about it. After this, cache memory was added to the CPU to improve execution

Then, the execution parts of the processor were duplicated. The ALUs, fetch and decode, instruction pipline, and some cache memory were organized into what we now call "cores". Each core is capable of functioning on its own and contain all the resources necessary to perform computational tasks that do not involve interacting with components outside the CPU. IO Control, interrupt handling, etc... were all shared between all the cores.

More recently the memory controller itself has been moved into the CPU package. It sits along side the CPU cores but it is not part of them. Thus it is part of the package, or part of the processor/CPU but it is not part of the 'cores'. Intel used to specifically refer to this as the 'un-core'.

This gets even more complicated when we talk about systems which have multiple physical processor packages installed. Many server and workstation platforms can have 2, 4, or even more processor packages installed. Each processor package contains the same hardware.

Thus, the number of 'cores' in a machine can be computed by taking the number of cores per package and multiplying it by the number of packages in the system. A computer which has two quad core processors has the same number of cores as a computer which has a single octal core processor.

Here is an image of a motherboard that has 4 processor sockets

http://i1-news.softpedia-static.com/images/news2/Tyan-Intros-New-Quad-Socket-AMD-Motherboard-and-Server-Barebone-Supporting-Up-to-512GB-RAM-2.jpg

Each one of those processor sockets (the flat ones with all the pins and metal coverings) can hold an AMD Opteron 6100 series processor. Each Opteron 6100 processor has either 8 or 12 cores inside which means that particular system can have between 8 (a single 8-core processor installed) and 48 cores present (4 12-core processors installed).