Computer Hardware:
     • Tools, Static & Cleaning
     • Form Factor
     • PC Case & Fans
     • Motherboard
     • Processor (CPU)
     • Power Supply Unit
     • RAM
     • Hard Drive
     • Solid State Drive
     • Optical Drive
     • Floppy Disk Drive
     • Graphics Card
     • Sound Card
     • Network Card
     • Computer Monitor
     • Keyboard & Mouse
     • Laptop / Netbook
     • Building a Computer
     • Overclocking

Operating System & Backup:
     • Operating System
     • Drivers
     • Windows Tools
     • User Accounts
     • Backup
     • Windows 10

Internet & Network:
     • Internet
     • Wi-fi or Cable
     • Improve Broadband Speed
     • Network Computers

Computer Peripherals:
     • Printer
     • Scanner
     • External Hard Drive
     • USB Flash Drive

Computer Security:
     • Anti-virus
     • Anti-Spyware
     • Phishing
     • Firewall

Common PC Problems:
     • Slow Computer
     • Hardware Failure
     • Software Failure
     • Printing Problems

     • Windows Shortcuts
     • Glossary of Terms
     • HTML Colour Picker
     • Number Base Converter

CPU Speed

CPU speed is commonly measured in Megahertz (MHz) or Gigahertz (GHz) which is the clock rate or frequency in which the processor is running.

However, comparing the speed of one processor against another is more difficult then just looking at the clock rate. You must also take into account whether the CPU has more cores, has hyperthreading as well as other CPU technologies, and also the size of the cache.

The internal speed of a CPU depends on the FSB (Front Side Bus) frequency and the CPU multiplier. To find the CPU speed you need to multiply the FSB with the CPU multiplier. For example, if the FSB is operating at 133MHz and the CPU multiplier is 10x then the CPU operates at 1330MHz or 1.33GHz.

Be aware that manufacturers usually quote the FSB as much higher (usually called Rated FSB) because an Intel FSB is quad-pumped and an AMD FSB is double-pumped meaning that data is transferred four times every clock cycle (Intel), or twice every clock cycle (AMD). A FSB of 133MHz would be quoted as a rated FSB of 266MHz for an AMD FSB (Double pumped), and a rated FSB of 533MHz for an Intel FSB (Quad pumped).


CPU and FSB.

It is possible to overclock a CPU to increase its speed by either increasing the CPU multiplier or by increasing the FSB speed. You will find that many processors will have a locked CPU multiplier which means you may only be able to increase the FSB speed. This is covered on the Overclocking page.

With the introduction of the AMD 64 CPU in 2003 and more recently the Intel Nehalem CPU in 2008, the Memory Controller has moved from the Northbridge to the CPU which significantly improves performance as the CPU can now access the RAM directly.

AMD 64 CPU & Intel Nehalem CPUs

AMD 64 CPU & Intel Nehalem CPU.

In the diagram above the CPU is directly connected to RAM and also connects to the chipset via the QPI (Quick Path Interconnect) bus on an Intel machine or via the HT (HyperTransport) bus on an AMD machine.

To work out the speed of the CPU you must multiply the Base Clock by the CPU multiplier. If the Base Clock is 133MHz and the CPU multiplier is 20x then the CPU will run at 2660MHz or 2.66GHz.

AMD Fusion (Bobcat) and Intel Sandybridge CPUs

AMD Fusion (Bobcat) and Intel Sandybridge CPUs.

The latest CPUs including the AMD Fusion (Bobcat) and Intel Sandybridge CPUs which were both introduced in 2011 have an integrated Memory Controller and Graphics (PCIe) which allows the CPU to access the RAM and Graphics (PCIe) directly without having to go through a Northbridge chip (see diagram above). In fact, the Northbridge chip is now integrated into the CPU. The CPU then accesses the Chipset (Southbridge) via the Intel Direct Media Interface (DMI) or AMD Unified Media Interface (UMI).