A lot of our clients have asked about getting some straight talk on computers. You get a lot of buzz words, acronyms and jargon out there and sometimes it's difficult to know who or what to trust when it comes to buying a computer. Hopefully this document will help you.
Computer speed and performance
There is a lot of misunderstanding and misinformation about computer performance. Most computer vendors will simply compare CPU speed or amount of RAM. A vendor will state that their computer runs at 900 MHz and has 128 MB RAM and because it's $50.00 less than a competitor many customers buy it only to discover that they've purchased a pig in a poke.
There is a lot more to computer speed and performance that just numbers. First of all no one component in a computer determines how fast a computer will run. All components work together to determine overall performance. Having a fast CPU but slow hard drive will result in poor performance, period. Don't let vendors sell you on raw numbers of one or two components. In determining performance all of these will affect the computer:
I'll deal with each item individually in detail and then wrap it up.
- System or Bus Speed
- Hard Drive
- Video Cards
The CPU (central processing unit) is the main computer chip that basically processes or runs any computer programs. When you see a computer advertised as a 900 MHz or 1.70 GHz, that's the CPU they are talking about.
First of all you will discover that there are different kinds of CPU's. There's the Intel Pentium, Intel Celeron and even the AMD. These are all very different CPU's and performance will vary from CPU to CPU even though all of them may have the same number (ie; 900 MHz).
First off, for our application, we DO NOT recommend the AMD chip. We ONLY recommend the authentic Intel chips. When comparing the Pentium class to the Celeron, the simple thing is that the Pentium is faster than the Celeron. An Intel Celeron might be good for home use on games and what not, but when it comes to running business applications the Intel Pentium is the way to go.
These days, you have various sub-classes of Pentium chips. At present there is a Pentium III and a Pentium IV available. No doubt there will soon be a Pentium V. There is a great deal of difference between the Pentium chips. In essence the Pentium IV has radically different architecture and is designed to run applications much better than a Pentium III. In addition the Pentium IV is superior in multi-tasking. That is, running 2 applications at the same time. A good example is burning a CD off the web while running a program. A Pentium III will slow down significantly, whereas the Pentium IV performs this far better.
In addition each Pentium (III or IV) has different speeds. This would be where we get into numbers like 900 MHz. Today, there are actually 2.0 GHz (that's 2000 MHz) chips. That is some wild performance.
Essentially the higher the class and higher the number, the faster the computer will perform. A Pentium IV with 2.0 GHz is far faster than a Pentium IV at 1.10 GHz. But there's more to it than that. While a lot of people will talk big on CPU speeds, they're 98 lb weaklings when it comes to system bus speed.
System bus speed
The system bus speed is determined by your main motherboard that works in conjunction with the CPU. Bus speed is kind of like the speed limit on a freeway. It determines how fast information can move through the computer. Bus speeds can vary from 66 MHz to 400 MHz these days. Naturally if the computer has a bus speed of 400 MHz it will process applications and programs much more quickly. The Pentium IV 1.80, 1.90 or 2.0 GHz can have bus speeds of up to 400 MHz. A Pentium III or IV at 1.10 GHz may only have up to 66 MHz bus speed.
When gauging performance, ask what the bus speed is.
Related to the motherboard and CPU are the amount of built in cache. This is extra memory that helps to manage and run programs. Most base computers will have level 1 cache of 32 KB and level 2 cache of 128 to 256 KB. The more the merrier.
Much like bus speed and built in cache, salespeople's eye's glaze over when you bring up hard drives. Most people will simply talk about the size of the hard drive such as 20 GB. Well that's one factor, and only one. There are many more factors when it comes to hard drives including:
When looking at hard drives, yes, get the larger sizes. A 100 GB is better in the long run than a 20 GB. You will use the space and your computer will perform better if it has a lot of room to work with. But don't forget about the items above.
- Average seek time - the time it takes to read and write retrieved data measured in milliseconds.
- Average latency - the time it takes for the hard drive to position itself on the part of your hard drive that has the information you want as measured in milliseconds.
- Rotational speed (how fast does it spin) - higher spin means faster hard drive.
- Buffer cache size - temporary data storage area designed to improve performance. Larger buffer cache size will increase performance.
These days average seek time of 12.0 ms is not very quick. Faster hard drives will have 9.0 ms or better. Likewise with average latency. A speed of 5.50 ms is not that quick. Faster units are at 4.20 ms or less.
Rotational speed is quite important. The basic rpm speed is 5400 but it's recommended to get the hard drives with 7200 rpm.
Finally buffer size. The higher the number the better. A good buffer cache size is now at 2 MB.
RAM memory greatly impacts on computer performance. This is internal memory that the computer uses to run your programs. Today you have two (2) choices for types of RAM. There's the slower SDRAM and the new and much improved Dual Channel RDRAM. It improves your performance because it allows you to spend less time waiting because it can load a new stream of data before the previous stream is even completed. RDRAM can also operate at faster frequency (ie; 400 MHz rather than 133 or 100 MHz like SDRAM). So the right choice is RDRAM and don't be stingy. If the basic amount of RAM is 128 MB, double it at least to 256 MB. This applies in the future as well. If the basic amount is 256 MB, double it.
Video cards are frequently overlooked when it comes to computers. However, their impact on performance is significant. Video cards also have RAM on board. This allows for the processing of complex screens with multiple colors. Displaying high end graphics takes a lot of power. The basic video card has 16 MB or RAM. However, you'll get better performance with 32 MB or even 64 MB by far.
Controller speed on video cards also affects performance and can vary from 130 MHz to 240 MHz. Faster controller speed will definitely improve performance.
The AGP bus speed should be 4x. Don't even bother with it if it's not.
Finally the data width should be 128 bit. Cheaper cards will only have 64 bit.
One item that causes grief is the use of integrated video cards on some systems. This is where the video card is built in to the board and does not have it's own memory. Instead it borrows system RAM. Guess what happens to your performance? Down the drain. They're cheaper and for good reason.
Basically, when you go out to buy a computer, you should be looking at the whole package, not just comparing engine size. Steer clear of home computers that are not designed for business use. Major name brands like Dell, IBM, Compaq and HP will carry business class computers as well as cheaper priced home computers. You WILL get what you pay for. No name brand shops usually cater to home users and don't normally have business class computers.
If you're looking at what to get, here's the run down:
- Business class computer from name brand outfit
- Intel Pentium IV CPU with 1.80 GHz
- System bus speed of 400 MHz
- Dual Channel RD RAM (the more the better, ie; double the basic amount)
- Larger hard drives with 7200 rpm
- 4x AGP 128 bit video cards with 64 MB RAM