Classic Computer Magazine Archive COMPUTE! ISSUE 168 / SEPTEMBER 1994 / PAGE 52

How to upgrade your computer's memory. (Compute's Getting Started With: Upgrading your PC.)
by Richard O. Mann

The simplest upgrade you can make inside the computer case is system memory. A few potential complications lurk here, but all you usually do is locate the sockets and plug in new SIMMs (Single In-line Memory Modules). You do, of course, have to open up the case to do this.

When Does More

Memory Help?

The primary need for increased memory comes when you adopt Windows or OS/2. Windows by itself uses more memory than most 286s ever had. Run a modern Windows application, and your memory is quickly gobbled up.

Microsoft would have you believe that a 4MB machine runs Windows without difficulty. That's basically true. With 4MB, you can successfully run many Windows applications, but virtually any major application released in the last year or so really needs 6MB to 8MB to run at an acceptable speed Don't even try to run WordPerfect for Windows 6.0 with anything less than 8MB, (I finally took it off my 4MB laptop - it was so slow that it was totally unusable.) You'll get the same results with almost any recent mainline application.

Recent research proves what many already knew: There's a "sweet spot" for Windows 3.1 at 8MB of memory. Performance speeds improve dramatically as you go from 4MB to 8MB. Further improvement as you move to 12MB and 16MB and beyond slows to almost none. You won't need 16MB or more with today's Windows applications (I make no promises for next year's software, however), unless you're working with ultralarge files (such as 10MB graphics or desktop publishing files) or you regularly need to run four or five large Windows applications simultaneously. OLE 2.0, the Windows feature that essentially embeds a whole application within another through linked objects, also benefits from memory beyond 8MB.

Types of Memory


You'll need to know which kind of memory sockets your motherboard has. The quickest way to find out is to have someone knowledgeable look inside the case, but your computer manual should tell you - if you can find it. A call to the computer vendor with serial number in hand should also net you the needed info.

If it's an older machine, you may have DRAM chips, which you have to remove and replace with higher-capacity DRAM chips in the same sockets, To go above 4MB in my old Northgate 386, I had to buy an expansion board to hold 1MB SIMMs after replacing the original DRAM chips.

If your motherboard has empty SIMM sockets, upgrading is a snap - just pop new SIMMs in, and you're done. If there are no empty sockets, you'll need to pull the existing SIMMs and replace them with higher-capacity SIMMs.

Another question is memory speed, quoted in nanoseconds. Lower numbers are faster. Older machines use 100-ns memory; newer ones use 70-ns SIMMs. Boyd Peterson of DeskTop Media in Salt Lake City recommends buying 70-ns chips even if your computer has slower memory now. The 70s will slow down to match the rest of the memory, and you'll have fast chips should you later decide to upgrade your

system further.

Memory currently runs about $45 to $50 per megabyte, making the move to 8MB an expensive proposition - especially if you're starting from 1MB or 2MB. If you're planning serious work with Windows, bite the bullet and write the check for the full 8MB.

The Easiest Way to

Upgrade Memory

If screwdrivers scare you and you're not sure which kind of memory chips you have or need, take the coward's way out. Find a helpful dealer and bring your computer case in. Have the dealer open it, figure out what kind of chips are needed, sell you the memory, and install it. The dealer can fire up your computer and make sure everything works before you leave the shop.


Upgrading your computer's motherboard: Now there's a scary thought. It has to be extremely difficult and expensive, right? Not so. Installing one isn't the easiest mechanical feat in the world to pull off, but it's not beyond the abilities of most of us. The cost is down in the $150 range - sometimes less. And the benefits can be dramatic.

What's on a motherboard? You can buy your CPU chip with the board, but for now we'll discuss the CPU separately. Your computer's motherboard is the home of its data bus, in the form of the expansion slots where you plug in boards and cards as well as the on-board circuitry. It has memory sockets, a CPU socket (and maybe an upgrade or OverDrive chip socket), BIOS chips, the memory cache, and the chip set (the rest of the necessary circuitry for running the computer). Your present motherboard may also have additional functions built in, such as the video adapter, drive controllers, and so forth. Upgrade boards generally don't have such built-ins.

As with CPU chips, not every computer will accept an industry-standard upgrade motherboard. Many proprietary clone makers make theirs sufficiently different to prevent the use of any new board except their own. Packard Bell, for example, charges $850 for a 386-40 upgrade motherboard that would otherwise cost around $129.

If you're going from a 386 to a 486 or Pentium, it will almost always pay to get a new motherboard in the process, according to Boyd Peterson of DeskTop Media in Salt Lake City. This way, your data bus can match the speed of the faster processor, and you're ensured that the BIOS and other components are new and compatible.

The primary issue in selecting a new motherboard is the type of data bus. The choices are the old Industry Standard Architecture (ISA), VESA Local Bus (VLB), and Intel's new Peripheral Component Interconnect (PCI) bus. The motherboard will have standard expansion slots and two or more VLB or PCI slots.

Local bus and PCI operate at much higher speeds and bandwidths than the old ISA bus, dramatically speeding up the movement of data through the computer. As computer makers decide whether to adopt VESA's new version 2 specification or PCI over the next half year, the winner will emerge.

In any case, get one or the other - forget the outmoded ISA bus. Peterson recommends local bus because the only cards currently available for PCI are video adapters and hard drive controllers. He also points out that only PCI-specific cards can plug into PCI slots - they're not backward compatible as local-bus slots are.

Another issue is built-in functions on the motherboard. Peterson warns that built-ins commandeer a set of hardware interrupts (the dreaded IRQs and DMAs you hear about) that may conflict with other cards, such as sound cards, video cards, and even parallel ports and game ports. Even when you can turn off the built-in functions, you don't get back access to those interrupts.

You may want to get a ZIF (Zero insertion Force) upgrade socket on your new motherboard - it's usually a $10 to $15 option - to allow for future chip upgrades.

And finally, dealers warn against looking for the absolute lowest price in upgrade motherboards. These bargain-basement wonders often use outdated BIOSs and chip sets as well as physically inferior materials. A decent motherboard isn't that much more expensive; go for high quality in such an integral part of your computer.