Software

What you need to build your PC, part 3: The video card and memory

Paul Suiter concludes his discussion of what to look for when you're putting together your own PC. This week, he examines different types of video cards and memory, and he makes suggestions based on your needs and circumstances.


In “What you need to build your PC, part 1: The power supply and the motherboard,” I gave a detailed discussion of the power supply and the motherboard. I talked about the hard drive and the CPU in “What you need to build your PC, part 2: The processor and the hard drive.” In this final segment, I will discuss the last two areas: the video card and memory modules. Although I talk about them last, they are by no means any less important than the other four parts that I’ve already covered.

Let’s take a look at video cards
A very difficult area to discuss is the video card (sometimes called the video adapter). Video cards are an extremely personal buy. What you want to see on your PC will determine the selection of the card. And everyone sees things differently. That’s why there are hundreds of video cards from which to choose, each offering different advantages and aiming at different users—from computer gamers to CAD professionals. I’ll give only a brief overview of what’s out there, but I’ll address some of the main aspects of a video board.

Video cards work in two environments: 2D and 3D. If you plan to use your computer mainly for word processing or spreadsheets, then buying a good 2D board would be in order. If you want to build a gaming or CAD computer, then you should look at 3D cards. Many cards have both 2D and 3D attributes built-in, but you should look more specifically at the way in which the card is designed. Does it lean toward the 2D side or the 3D side? Also available is the 3D add-on card. Designed to provide only 3D graphics, this card works through your existing video card but adds enhanced 3D graphics to your system. It isn’t a stand-alone card; it must ride “piggyback” on another card in order to work. Thus, another expansion slot will be taken up on the motherboard, which is an issue that you should consider carefully if you plan on using several expansion cards.

Currently, two main connector and bus types for video cards are in use. The most frequently used connection and bus is Peripheral Component Interconnect (PCI). The PCI bus has given video cards a great boost over the ISA and VESA bus. It has provided a much faster rate of data transfer, and it has led to great leaps forward in the use of 3D graphics for gamers. But it still has to go through a data bus, which creates a bottleneck because of the limited amount of data that the bus can push through to the system’s memory. A PCI 2.1-compliant bus operates at only 33 MHz, and it’s only capable of transfers of about 100 MB per second. Most systems today operate at 66 MHz (if not higher) for both the processor and system memory.

Intel went further and created a connection that would bypass the slower PCI bus and go straight to the system memory at a 66-MHz bus speed. This development turned into what is now called the Accelerated Graphics Port (AGP). This new bus is designed strictly for the video card, and it has no other responsibilities, which allows the bus to work at almost 100 percent efficiency and to use the system’s memory in unison with the video board’s own memory.

Generally, the 3D board will have its own processor for 3D rendering and its own video memory. This processor will handle much of the 3D rendering that’s needed by a program. It takes a big strain off of the CPU and allows the CPU to work in other important areas without hindering either part’s performance. Be sure to note the name of the processor that the board uses. Many current 3D programs are written for specific types of processors. Using different 3D engines for various programs will work well with some boards but not so well with others. This is a major consideration for anyone who plans to use high-end 3D rendering programs. Some of these programs may be designed specifically for certain 3D processors.

If you’re building a PC for general use, you’ll find an ample variety of choices, and you’ll see that the prices are quite low. 2D has pretty much hit a ceiling as far as improvements can go. That limit, in turn, has brought prices down for most of the older cards. 3D graphics, on the other hand, are still evolving. Companies constantly come out with faster and better video processors and keep the price up on high-end 3D video cards. So, expect to pay more for newer technology.

Don’t forget about memory!
It’s easy to forget about memory (no pun intended). You’ve finished buying the “big” pieces, and you’re down to that “small” purchase of memory. With all of those new types of motherboards and CPUs, however, you had better make sure that you get the right memory, or your system will suffer for it.

As I said in part 2 of this series, you must purchase memory that matches the external clock speed of your CPU. Memory is sold in three different speeds: 66 MHz, 100 MHz, and 133 MHz. In order to obtain maximum efficiency in your system, you should ensure that the CPU, the motherboard, and the memory match. That’s not to say that the system won’t run if your clock speeds don’t match. What you end up with, however, is a bottleneck that causes your system to run at the lowest clock speed, regardless of which component causes the bottleneck.

You can purchase the higher clock speed in memory and run it at a lower speed if you like, but it’s probably a waste of money—unless you plan on upgrading in the near future and reusing your memory. For example, you can purchase 133-MHz memory and use it now with a 100-MHz bus motherboard if you plan to upgrade to a 133-MHz motherboard. However, doing so won’t speed up your 100-MHZ system; the 133-Mhz memory will run at the slower speed and waste the memory’s additional capacity.

The prices vary little among the three speeds but vary widely between the two types of memory. There are different connections for power supplies, CPUs, and drives; the same holds true for memory. The two types of connections on motherboards for memory modules are the 72-pin Single Inline Memory Modules (SIMM) connection and the 168-pin Dual Inline Memory Modules (DIMM) connection. In some cases, you may find motherboards with both connections. In general, however, older motherboards have several connections for SIMM, and newer motherboards have two or three connections for DIMM.

Not only must you consider the clock speed and the type of connection, but also the type of memory. There are more memory types than I care to mention, and some types have no bearing on your purchase. So, I’ll cover just a few of the types that you’ll probably come across and want to purchase:
  • Dynamic Random-Access Memory (DRAM) serves as the basis for the memory modules that are common in today’s computers. You’ll find DRAM used with SIMM memory modules. It’s one of the oldest memory types, but it remains in use in the lower-end systems. The drawback to this type of memory is that the bits of information within the memory modules have to be refreshed continuously, or they will degrade. It’s also slow in access time, which causes a bottleneck for fast CPUs.
  • Extended Data Output Random-Access Memory (EDO RAM) is the norm for most middleweight computers, and it has become the standard that’s supported by most motherboards. EDO RAM received its unusual name because it holds data in memory until it’s told to release the memory—thus extending its time within the memory bus. EDO RAM is backward-compatible to older motherboards, but it offers no improvements over DRAM.
  • Synchronous Dynamic Random-Access Memory (SDRAM) is found primarily on modules that use DIMM connections. The advantage to SDRAM is that it’s capable of the higher bus speeds of 100 MHz and 133 MHz. SDRAM also offers a pipeline burst that can reach data transfer rates of 100 MB per second. Although SDRAM is the most expensive of the types that I’ve discussed, it’s the type of memory module that you should purchase if performance is your main criterion.

When purchasing SIMMs, you should keep in mind that these modules are often sold in pairs. So, if you plan on having 32 MB of memory, you usually need two 16-MB modules or four 8-MB modules. Usually, it’s best to purchase memory from the same manufacturer who built the module that you use (EDO, FPM, etc.). With newer motherboards, mixing the types is possible, but doing so causes small glitches that are very difficult to pinpoint. You should check your motherboard’s manual to see what kinds of memory it requires and in what combinations.

DIMMs, on the other hand, are a single unit that can hold large amounts of RAM—sometimes as much as 256 MB on one module. You don’t have to purchase them in pairs. They are taller and longer—hence their ability to hold large amounts of RAM. Since they are also thinner than the SIMM type, the DIMM connectors occupy a more confined area. You’ll find that, due to their smaller size, many ATX motherboards have only DIMM slots.

Conclusion
The types of hardware that I’ve discussed in these Daily Drill Downs can be combined in many different ways. I merely offered a brief discussion of the main parts of a PC system. The purchaser of this equipment must perform adequate research to ensure that the parts will fit properly with other purchases. I also tried to allay some of the fear that many people feel when they try to build their own PCs. If you create and build a PC for and by yourself, I promise that you’ll experience a wonderful feeling of accomplishment.

Paul Suiter received his first taste of the deadline rush as a photographer for the Montgomery Advertiser, where he earned four photography awards. After receiving degrees in economics and business management from Auburn University, Paul entered the college book business. After managing two bookstores for three years, Paul became a business analyst for EDS. Four years later, Paul continues with EDS, taking its equipment apart, while working with G3 switches and advanced imaging programs. But he’s finally getting back to one of his favorite pastimes—writing. (Of course, he also enjoys spending time with his wife and son.)

The authors and editors have taken care in preparation of the content contained herein, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.

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