Since the introduction of the Intel Core i3 CPU in 2010, every major processor niche for Intel and AMD has been a dual core processor. The higher end processors have four, six or even eight cores. Modern operating systems, such as Windows 7 and later, make taking advantage of a dual-core system much simpler than it used to be.
A dual-core processor is a chip that fits into a motherboard with two central processing units, or cores, rather than one. Those cores have a very fast communications path between them, and often have shared high-speed memory, and separate pools of slightly lower-speed memory that each accesses individually. The exact particulars vary by manufacturer. Chip manufacturers couldn't keep increasing processor speed on a single core processor due to heat issues. Multiple-core processors allow more performance with fewer thermal concerns.
How They Work
When you have one program running on a single core processor, that processor is devoted to that program. When more than one program is running, the processor does a part of each program and switches back and forth between them. This constant switching adds overhead to the computation. Add enough programs and the switching out causes enough overhead that the computer becomes sluggish or non-responsive. On a dual-core or multi-core processor, each program can be assigned its own processor. The operating system balances the load between multiple programs to keep both processors busy. If a program has been written specifically to take advantage of multi-core processors, it's called a multi-threaded program. Each task the program does is broken into sub-elements called threads that the operating system can assign, on a per thread basis, to whichever processor is least busy. A part of the operating system called the branch prediction manager, or scheduler, can queue up threads so that the minimum amount of time is spent waiting for threads to complete.
Use Windows 7 64-bit
Microsoft Windows 7 -- especially the 64-bit version -- has significant enhancements in its scheduler to allow the operating system to make the most of a multi-core processor. Many basic utilities were rewritten to be multi-threaded as part of their revisions to handle 64-bit memory access. This type of memory access allows a computer to access more memory, and allows it to read and write that memory in larger chunks; it is a separate performance improvement from the number of cores within the processor.
Use Multi-Threaded Software
When dual-core processers were new to the market, very few programs were specifically optimized for them; the primary exceptions were 3-D rendering programs, video editors and image editing packages. As more software has been rewritten to take advantage of 64-bit memory addressing, much of it has been made multi-threaded as well. Examples of programs that have become multi-processor aware include Microsoft Excel 2010, Adobe Photoshop CS5 and Microsoft Access 2010.
The Invisible Benefit
A large number of dual-core processors are in laptops. In addition to providing their facility with multiple programs, multi-core processors have per-core power management. When the computer is only using a single processor, the other is set to a low power state to save battery life.
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