CPU stands for Central Processing Unit and it is one of the main components of a server. If you are thinking of ordering a VPS then one of the features that you need to consider is how much CPU to order.
The CPU basically controls the function of the server, a bit like a brain in a human. It sends and receives instructions to all of the main components like RAM, Hard Drives, power supply, etc..
Main Components of CPU
The main components of a CPU are as follows:
A Register is fast storage located on the CPU and is used for storing data that the CPU requires to run programs. A CPU typically has many Registers.
CPU Memory (RAM)
In order to reduce the complexity of the CPU they will only process instructions via the Registers that they are working on at that time. The remaining data is kept external from the CPU in RAM memory and is called upon when required.
As the RAM is slower than the CPU Registers Cache memory is used directly on the CPU. Cache Memory is much more expensive than RAM Memory and therefore its use is minimised and it calls on the RAM to provide data when required for faster processing.
Buses are the wires that link the CPU to the RAM and other components of the server.
CPU Instruction Set Architecture
In order to communicate instructions to the CPU a special type of language called ‘instructions’ is required. These languages are written in Binary (Machine Code) – basically a series of zeroes and ones (0,1).
Computer programs are not created in Machine Code so they require either a Compiler or Assembler to translate them.
CPU speed is measured in Hertz (Hz) and the typical measure for modern processors is Gigahertz (GHz) where 1GHz is equal to one billion cycles per second.
Modern CPUs consist of multiple CPUs called ‘Cores’ to allow them to run multiple instructions simultaneously. You will often hear CPUs referred to as 4 Core, Hex (i.e. 6) Core, 8 Core, etc..
These numbers represent the number of physical cores on the chip.
Virtual CPU Cores (Logical Cores / Threads)
However, you will sometimes hear Cores referred to as Virtual Cores (vCores), Logical Cores or Threads. For example the Intel i7 quad core has 4 Physical Cores and 8 Logical Cores (Threads).
A Thread is a sequence of Instructions so a CPU with 8 Virtual/Local Cores (Threads) can process 8 Threads simultaneously (i.e. 2 per Physical Core).