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Buying Guide for CPU's
Buying Guide If you had a chance to choose a brain, wouldn’t you have chosen Einstein’s? A Central Processing Unit (CPU) is the brain of the computer. And there’s no compromising/shortchanging on it. When one refers to a CPU, what first comes to mind is the box, case or cabinet that houses the hard disk, CD-ROM drive, etc. This is only partially true. The CPU is in essence the microprocessor that is affixed on the motherboard. The CPU is the core of your computer's operations. It controls the flow of data throughout your entire PC. Microprocessors and CPU are terms used synonymously/interchangeably. At the time of purchase of a CPU it is important for you to take into consideration the types of motherboard that a CPU is compatible with, the additional capabilities that you're looking for in a processor, and also the types of software you're likely to run on your machine.
Functions | Characteristics | Intel | AMD | Conclusion

1 - Understanding its function

A Microprocessor is an Integrated Circuit (IC) comprising millions of transistors etched onto a silicon layer. Transistors store information in binary (on/off) form, and it is from these on/off states that more complicated processes are performed. A CPU in order to perform any task needs a few basic components. Each processor however, differs in its architecture. A CPU needs to be able to get data in, transform it meaningfully based on the instructions it is given, and then send that data to a suitable repository. The repository could be a storage medium such as a hard drive, a visual display (monitor), or even the CPU itself for further calculations.

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2 - Characteristics that differentiate

2.1 - Bandwidth

The number of bits that can be processed in a single instruction. The higher the number the better, of course all this would come at a premium of price.

2.2 - Clock Speed

In order to correctly synchronize the actions of a CPU, a metronome-like clock sends deliberately timed pulses throughout the CPU. This is referred to as the clock cycle, and is typically measured in gigahertz. Clock speed is a combination of the Front Side Bus, speed of the motherboard and the clock multiplier of the CPU. It is advisable to take clock speed into consideration at the time of purchasing a processor. Given in Megahertz (MHz) or Gigahertz (GHz), the clock speed determines how many instructions per second the processor can execute. A 32-bit microprocessor that runs at 50 MHz is more powerful than a 16-bit microprocessor that runs at 25 MHz.

2.3 - Architechture

In addition to Bandwidth and Clock speed, microprocessors are classified as being either RISC (reduced instruction set computer) or CISC (complex instruction set computer). 32-bit processors follow the CISC architecture while 64-bit processors and those that are used in high end computer systems such as mainframes and imaging workstations follow the RISC architecture. CISC architecture based processors are much cheaper to those of RISC.

2.4 - Cache

It is the i nternal memory on the processor. It is an addition to the memory or RAM usually available on the motherboard and is physically part of the processor. Cache is split up into levels, which relate both to the size of the cache and its access speed. There are three types of cache:

  1. L1: This cache is small but with a fast access time, making it the first place the CPU would go to search for data.
  2. L2: Larger than the L1 cache in terms of storage. If the required data is not found in the L1 cache then CPU will search for it in this cache. This may take more time compared to the search in the L1 cache for the data stored in this cache.
  3. L3: This cache is largely associated or used for server CPUs; however it is starting to become a feature of some consumer desktop processors.
  4. L4: Boosts processors function by providing fast access to data and application codes at unheard of speeds.

2.5 - Front Side Bus (FSB)

It is the primary connection point between the CPU and the chipset on the motherboard. The speed of the CPU is determined by the combination of FSB speed and the processor's internal multiplier. FSB speeds range between 533 MHz and 1066 MHz. It is important to note which FSB speed your motherboard supports.

2.6 - Overclocking

For those with an eye for increasing the endurance of the CPU, this feature is important. Overclocking is done by altering the frequency at which the CPU is run. By altering either the FSB or clock multiplier, you can increase the overall frequency of a given processor. For this, you need overclocking to be supported on both the processor and the motherboard. This enables the CPU to perform at faster speeds. There is a distinct danger of the chip overheating by it running faster than it has been safely clocked at, for obvious reasons. It is advisable to overclock your processor only if you have done it before or if you’re an expert. Please ensure that you do insert extra cooling mechanisms such as; fans or heat sinks to dissipate the excess heat generated by the processor.

2.7 - Fan and Heat-sink

To dissipate the heat generated by the processors during its functioning all current processors and some old ones are provided with a fan normally placed above the processor. Nowadays processors come with heat sinks, some with fans (active heat sinks) and some without fans (passive heat sinks). A heat sink is a component designed to lower the temperature of an electronic device by dissipating heat into the surrounding air. If you plan to use your computer excessively, for long periods of time, for gaming purposes or other activities that load the processor, then it is important that you take into consideration that proper heat dissipation components are in place.

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3 - Brands Available

The microprocessor segment is dominated by the Intel range of products, but slowly and steadily AMD and via are posing good competition and have developed a healthy customer base for themselves.

3.1 - Intel

  1. Pentium
    Pentium is the most popular range of processors from Intel.

  2. Celeron
    Celeron is a low cost processor that supports Slot 1 motherboards. It has a 128-bit L2 cache.

  3. Xeon
    Xeon is a follow up of the Pentium Pro. It is a processor that runs the L2 cache as fast as the processor itself. This is targeted at servers with a Slot 2 cartridge and an L2 cache of 512K.

  4. Itanium
    Itanium is the first 64-bit processor from Intel using their Explicit Parallel Instruction Computing (EPIC) standards. This range supports the L1 and L2 cache while adding L3 and L4 cache to the processor. The L3 cache has a storage area of 2or 4MB and is capable of supporting 16GB of main memory or RAM.

3.2 - AMD

  1. Athlon
    Athlon is the first processor which supports Symmetric Multi Processing (SMP). The processor is the first non-Intel product that offers this function. It has 512K of L2 cache and supports 19 new instructions for 3-D via a 128-bit pipeline.

  2. Duron
    Duron is the low end version of the Athlon supporting a Socket A interface with 64K of L2 cache.

  3. Opteron
    Opteron is the first processor from AMD to support both 32-bit and 64-bit computing with 1MB of L2 cache. Ideal for high end computing and is targeted at Servers and Workstations.

  4. Sempron
    Sempron is a 32-bit processor supporting a Socket A motherboard. It comes with 256K of L2 Cache. It is cheaply priced, with low end users in mind.

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4 - Conclusion

In order to get your processor to function well, you must ensure that the FSB speed is matched with the processors speed. This is of paramount importance. It is also important to take into consideration the cache or memory offered. Last but not the least; care must be taken to ensure that the motherboard has the right type of slot/socket to support the processor that you have in mind.

You don’t often get to choose a brain. So when you do, be certain you make the right choice.

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