On the matter of memory, there is bad news and there is good news. The bad news isn't terribly bad, but it is unprecedented: For the first time in the history of semiconductor Random-Access Memory (RAM) chips, the price of computer memory is going up.

Since the first RAM chips were produced in 1968, memory chips have been the paradigm case of productivity gains leading to lower prices. As makers learned to squeeze more capacity onto each chip, the price of memory dropped, and dropped, and then dropped some more.

In December 1984, for example, I bought some RAM chips that hold just over 64,000 characters -- that is, 64K RAM chips -- for $4.10 each. That came to about 6 1/2 pennies per 1,000 bytes of memory. At the time, this was a fairly good price. In November 1985, I bought some 256K RAM chips. Price: $2.40 each. In just 11 months, the price had fallen to less than one penny per 1,000 bytes. Today, though, the same chips I bought for $2.40 about nine weeks ago cost $2.85, and the supplier says the price is heading up even more.

What powerful force could muck up the market so badly as to reverse 18 years of declining prices? It was your friendly Uncle Sam. After the federal government announced last fall that it would investigate some Japanese makers of memory chips on suspicion of "dumping" (that is, selling the chips at an artificially low price), the price of foreign-made memory chips began to go up. This reduced the competitive pressure holding down the price of domestic chips.

It's hard to get upset about this, because the price of memory is still amazingly low by historic standards. From the consumer viewpoint, though, any price increase has to be considered bad news.

The good news on memory, however, will offset the mild increase in RAM chip prices. Some ingenious folks in the hacker community have come up with an inexpensive way to upgrade the memory in most MS-DOS computers to 640 kilobytes of RAM. The main circuit board, or "mother board," inside an IBM-PC or compatible has room for four rows of memory chips. Using the 64K RAM chips that are standard equipment on most personal computers today, that means a maximum of four times 64K, or 256K, of RAM can be installed on the "mother board."

The problem with this limit is that many of the best software applications today need more than 256K of memory. To meet that need, IBM and other suppliers will sell you a supplemental memory circuit board; these can normally hold up to 384K of additional RAM, for a total of 640K.

But these memory boards take up one of the expansion slots inside the computer -- a significant concern in some machines. And the boards cost real money: between $175 and $300 for the circuit board alone, with no memory chips installed.

So here's a paradox: the additional memory chips needed to increase the computer to 640K of RAM are extremely cheap, but the circuit board that holds those chips is expensive.

Now some clever computer buffs have eliminated the paradox. You can buy a cheap, simple upgrade kit that will permit you to install the full 640K of RAM on the "mother board" of your computer. All you have to buy are the memory chips. There's no need to buy the expensive supplemental circuit board.

This bit of magic is achieved by replacing two rows of 64K RAM chips on the mother board of your computer with 256K RAM chips. You also stick on one or two new "memory decoder" chips to enable your computer to use those new 256K chips. This leaves you with two rows of 256K chips, for 512K of RAM, plus two rows of 64K chips, for 128K. Total: 640K of RAM. Price: between $50 and $75 for everything, and 30 minutes of your time.

This upgrade is a snap to install, even for the total technoklutz. You have to buy the RAM chips yourself -- about $50 worth -- but they're available from 100 mail-order houses.

An outfit called Innovention (telephone 713=728-0938) sells an upgrade kit for the Compaq portable for $29; an IBM-XT version is $49. RAM Technology (603=889-0633) has a $25 kit for the Zenith Z-150 series. Microprocessors Unlimited (918=267-4961) sells a kit for certain IBM and Compaq models for $20; it may work on other compatibles as well. MaxRam (Box 33060, Denver 80233, check or money order only) has two kits for the IBM-XT or IBM portable; kit I costs $5 and requires soldering one wire; kit II costs $10 and requires no soldering.