I'll be buying a new computer in the next couple months and want to understand the dual/duo/two CPU issue:

  • Core Duo CPU (is this one "duo" CPU or two?
  • Quad Core (four cpus?)
  • Dual CPU (two cpus?)
  • 2 CPUs (does this always mean two physical chips?)

I can look these up on Wiki, etc. but it's just an explosion of new terminology. What is the simplest way to understand this "two CPU" thing for someone who:

  • is a developer and wants to begin testing out e.g. threading issues on two CPUs
  • does not play video games
  • will be doing screencast recording (camtasia)
  • want the computer as fast as possible, e.g. 20 applications open, constantly downloading, streaming music, videos etc.
  • 1
    Remark: »Core Duo« is a Intel CPU derived from the Pentium M, which means it is a 32 bit CPU and designed like Pentium processors. »Core 2 Duo« is a completely new 64 bit architecture. I would suggest buying a computer with the new Core 2 Duo CPU rather than the »old« Pentium. – Manuel Faux Jul 30 '09 at 18:21

Core Duo CPU = Intel's line of dual core processors. This means that there are two logical CPU's on a single chip.

Quad Core = Four logical cpu's on a single chip.

Dual CPU = two chips (normally with a single core, but you can do multiple chips of multiple cores as well)

2 CPUs = What it says, two CPU chips

The beauty of multiple processors or multiple cores on a single processor is the ability to perform multiple instructions at the same time in parallel instead of having to wait for one instruction to finish before starting another. This can make it much faster and efficient to perform CPU heavy tasks such as video editing, graphics, gaming, etc. You will only see performance benefits from applications that effectively utilize multithreading, otherwise it will NOT utilitize multiple cores/processors or at the most will rely on any built-in multithreading capabilities of the OS.

Multiple cores/processors can help with multitasking significantly, but you will still have to contend with other potential performance bottlenecks such as the amount of available RAM on your system. If you don't have enough RAM to run all of those processes, it is not going to matter a whole lot how many processors you are banging out instructions on.


  • 1
    As for other processors: AMD X2 is AMD's dual core line, Phenom is their quad core line. – RascalKing Jul 30 '09 at 18:25
  • Correct, Rascal. – TheTXI Jul 30 '09 at 18:33
  • 1
    Phenom (II) can have 2, 3 or 4 cores. Phenom II X3, would be a 3 core Phenom (actually 4 core with one /disabled/) for AM3 platform. – Joakim Elofsson Jul 30 '09 at 19:40

Types of CPUs:

  • Single Core CPU - 1 chip, 1 Core
  • Dual Core CPU - 1 chip, 2 cores
  • Quad Core CPU - 1 chip, 4 cores


  • Dual CPU - 2 chips, ? cores (depends on chips)


  • Core 2 Duo - Intel name-brand for dual core CPUs (see dual core above)


A single core system has 1 chip with 1 core.

A dual CPU quad core system has 2 chips with 4 cores each.

A dual core system has 1 chip with 2 cores.

A "core" is a logical CPU contained in a physical chip.

For most situations, you're only going to need 2 CPUs (dual CPU) if you're running a server or you're on a dev machine testing out something that will run on a dual CPU machine. Otherwise, you're pretty much good to go with just a dual core chip; quad core if you're really going crazy.

  • 1
    When is a "core" not a physical CPU? Unless I'm mistaken, each "core" maps to a distinct physical set of transistors. So, while it's on the same package (usually same die/chip) it's a physical CPU, no? Lowering the criteria to logical makes it sound like single-core CPUs with "HyperThreading" would qualify. – NVRAM Oct 23 '09 at 20:44
  • I'd agree that for most people dual cores should suffice, but in addition: if the machine uses virtualization then more cores may make a lot of sense. But VMs on a machine that isn't a dev or server seems less likely. – NVRAM Oct 23 '09 at 20:48

"CPU is a central processing unit. A hardware, chip. only one cpu inside of a pc. "
"Core 2 Duo - is the name given by Intel processors"
"Dual Core - means it has two core inside of the cpu"
"Quad Core - means it has four core inside of the Cpu"
"Two CPU - ? literally two chips of CPU."

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