Don’t be fooled by computer vendors

[Tradução para português aqui]

I’ve been asked several times by my friends which processor is better: Sempron, Athlon, Pentium, Celeron, etc. Indeed, a multitude of options is available these days: processor (CPU) clock (processor frequency or speed), L1 and L2 cache, dual core as well as Hyper-Threading technology. This is further complicated by the fact that the user also has to choose RAM size and hard disk capacity. Being the triad processor, memory and hard drive the basic things to take into account when buying a new computer, I’ll briefly explain them in order to help the average user to decide and not to be fooled by vendors, whose only purpose is to sell the most expensive system.

The memory

Firstly, memory or RAM (Random Access Memory) is the memory used when the computer is on and it’s measured in megabytes (MB) or gigabytes (1 GB is basically 1000 MB). If you’re the kind of user that likes to run a lot of programs and is not willing to close your browser to either open a word processor or scan a picture, you need more RAM. Plus, if you want to leave your computer on for several hours or don’t turn it off at all (like me), you also need more RAM¹.

The reason that you need more memory is not that you would not be able to run your applications, but the performance of your system will be impaired by the fact that your operating system will have to ‘page’ the extra data. Paging is the process by which, due to the lack of physical RAM, the operating system has to write the extra information on the hard drive. The movement of a hard drive head to read and write data is measured in thousandths of a second, while in the case of RAM, it’s performed in billionths of a second. That’s a factor of a million! Thus, if you’re planning to buy a computer with 256 MB, forget it; the performance of your system will be severely compromised, even with the fastest processor on the market. The minimum for Windows XP is 512 MB, but I would recommend 768 MB. Unless you’re a hardcore gamer or like virtual trips with Google Earth, 1 GB and over won’t necessarily improve the performance.

The processor

Things get a little bit more complicated regarding processors, because of the fact that there are lots of them on the market, although they’re manufactured either by Intel or AMD. First check the frequency of the processor, which is measured in gigahertz (GHz – billions of ‘pulses’ per second). You’d think that the higher, the better; however this is not always true. In fact, you also have to check the cache memory (L2 cache, specifically). Cache memory is a very fast type of RAM that is embedded in the processor and it’s useful when the application requires a set of instructions to be repeated. Instead of requesting them from the RAM, it reads from the cache. For instance, Intel Pentium D processors are faster than Celeron D processors, considering that Pentium has L2 cache around 1000 KB, whereas Celeron has 256 or 512 KB, even though running basically at the same frequency. This is also the case of laptop processors: despite the fact that their clock speed is usually lower in order to save energy, they have a larger L2 cache.

As I’ve mentioned above, computer “brain” choice is a hard issue. Newer processors are released every month or so. A new wave of CPUs is now on the market: dual core processors. They feature the same structure of the single core processors (clock speed, cache memory), but they possess two units (CPUs) on the same chip. Obviously, this doesn’t make your computer run twice as fast, but their efficiency is considerably augmented, along with their prices. Additionally, there is Intel’s Hyper-Threading technology (HT Technology; not AMD’s Hyper-Transport technology) that works by making more efficient use of idle clock cycles, processing more than one thread (or piece of the same application) at the same time.

The hard disk

Finally, the hard disk capacity depends on what you want to save in computer. I’d recommend a faster hard disk (SATA – Serial ATA; virtually all desktop systems use this technology nowadays) and a large hard disk cache memory (8 MB or 16 MB). Generally, 60 GB is more than enough to install every software you need plus 10 GB of songs, that is, approximately 7 days of non-stop music. Of course, 80 GB or more sounds better, especially if you’d like to have lots of movies in you hard disk and you’re not willing to search for them in some CD or DVD spindle. Nevertheless, this problem can be circumvented by purchasing an external USB (and slower) hard drive with 160GB or more.

Conclusion

I hope this article would have answered some questions for the non-experienced user without being too technical, although you might come up with other questions. That’s it. Post your comments!

1. To check how much memory you have, press CTRL+ALT+DEL and click on the performance tab. In ‘Physical Memory’ you can verify the ‘Total’ memory in kilobytes (KB – 1000 KB is approximately 1 MB) in your system. Also, in the performance tab check ‘PF Usage’, that is the memory that is being used at any given time.