Factors that affect a CPU performance

Factors that affect a CPU performance

It is easy to think that the speed of the CPU is directly link to the performance of the CPU. In actual facts, this is only true to a certain extent. A CPU with fast speed will not be efficient if it has only a limited data to process each time. To achieve maximum efficiency, the hardware (especially the hard drive and memory) that linked to the CPU must supply data as fast as the CPU speed. Failure to do this will result in a lagging computer, regardless how fast the CPU is.

Below, let’s look at the other factors that affect the CPU performance.

CPU Clock Speed

The operating frequency of the CPU (also known as the clock speed) determines how fast it can process instruction.

The speed is measured in terms of Hertz, and it is usually lies in the megaHertz (MHz) or gigaHertz (GHz) range. A megaHertz means that the CPU can process one million instruction per second whereas a gigahertz CPU has the capability to process one billion instructions per second. In today technology, all CPUs run in the gigahertz range and you seldom see CPU with speed in the MHz range anymore.

Theoretically, a 500 MHz CPU is six times slower than a 3 GHz CPU. Equally, a 3.6 GHz CPU is faster than a 3 GHz or a 3.4 GHz CPU. In general, the higher the frequency of a CPU, the faster the speed of the computer.

Cache

Remember we mentioned above that for the CPU to work at its maximum efficiency, the data transfer from the other hardware must be as fast as its speed? The purpose of a cache is to ensure this smooth and fast transition of data transfer from the hardware to the CPU.

To understand how the importance of a cache, it is necessary to understand how the whole process works.The main bulk of information comes from the hard drive. When an application is requested, the motherboard will fetch the required information from the hard drive and deliver it to the CPU for processing. Since the hard drive processing speed is much slower than the CPU, data transfer often takes a long time. To fasten thing up, the RAM is used to store temporary information from the hard drive. Instead of heading straight to the hard drive, the motherboard now checks and retrieves the data from the RAM. Only when the required information is not found in the RAM then will the motherboard go to the hard drive.

As CPU speed increased to the point where the RAM is no longer able to catch up, the transferring of information again become a serious problem. To solve this issue, a cache, which was effectively a small and extremely fast memory, was added to the processor to store immediate instruction from the RAM. Since the cache runs at the same speed of the CPU, it can rapidly provide information to the CPU at the shortest time without any lag.

There are different levels of cache. Level 1 (L1) cache is the most basic form of cache and is found on every processor. Level 2 (L2) cache has a bigger memory size and is used to store more immediate instructions. In general, the L1 cache caches the L2 cache which in turn caches the RAM which in turn caches the hard disk data.

L2 cache plays the greatest part in improving the performance of the processors. The larger the cache size, the faster the data transfer and the better the CPU performance. However, cache is very costly. That is why you don’t find 1GB of cache in your system. The typical cache size is between 512KB to 4MB. The latest Core2 Extreme Quad core features 12MB cache (which also explains its hefty price tag of $1,499).

Multi-Core

In the past, if you want to get a faster computer, you have to get a faster CPU. Today, this is only partially true. The reason being, CPU speed can’t increase forever. There is limitation as to how fast the transistors can run and when it reaches a plateau, you won’t be able to increase the speed anymore.

To tackle this problem, CPU manufacturers (in this case, Intel and AMD) adopted a multi-core technology, which literally means putting multiple cores in a CPU chip. While increasing the CPU speed resulted in faster data calculation, putting more cores in a chip resulted in more work done at the same time.

At the moment, the most prevalent CPU are mainly dual core. You can also find quad-core CPU at a higher price range. Soon, you will be able to see six-core and octo-core CPUs to hit the market in the next 1-2 years.

In the next page, we will find out whether Intel or AMD CPU is better.