President Bush, like most chief executives, doesn't use a personal computer. But just down the hall from the Oval Office in the West Wing of the White House is the office of the nation's First Nerd. He is White House Chief of Staff John Sununu, and beside his desk sits a personal computer worthy of his status. It is a 20 Mhz Compaq 386 with four megabytes of memory, a 110-megabyte hard disk, VGA graphics and monitor and a Hewlett-Packard Laserjet II printer. It is equipped with an "Irma" board to connect his system with the IBM mainframes that handle heavy computer duty for the White House and Office of Management and Budget (OMB). The White House is almost an all-IBM shop, so how did Sununu get his Compaq powerhouse? "The guys asked me when I came in what I wanted and I told them," he said. One of "the guys" in the White House data-processing office remembers it slightly differently: "It was more like, 'This is what I want,' " he said. Either way, it seems money can be found for some big-ticket items even in a budget crunch. Sununu, an engineer, is an old hand at computers, having done programming on mainframes back when it was entered on punch cards. When he was governor of New Hampshire, he had an IBM AT, which he used to download budget and purchasing data from the state's mainframe system. Sununu used a Lotus 1-2-3 spreadsheet to analyze the numbers. "I could watch the department accounts from my office," he says, and Sununu's detailed grasp of what was going on in state government is something of a legend. He's got Lotus on his White House system, too, but despite the number-crunching power of a 386, he doesn't attempt to keep track of the federal budget. "This is a different job," he says. "When I need budget stuff, that's what OMB is for." Sununu confesses his system sits largely idle: "I just haven't had a chance to get the full flavor of it. I am frustrated. I keep looking at it. I want to take a weekend off and come in and just do it." So far, he says, about all he's been able to do is play a couple of games -- Bermuda Squares and the popular global-strategy game, Balance of Power, which could presumably help Sununu with his feel for foreign policy. Despite that huge hard disk, Sununu just boots the games from floppy disks. And he hasn't learned the word processor because he uses a secretary for correspondence. The White House secretaries, meanwhile, are in the throes of transition from IBM's Displaywrite IV to WordPerfect. The IBM program was originally adopted because the White House had a lot of Displaywriter word processors. And Displaywrite, which is similar, made word processing on PCs easier. But the Bush transition team used WordPerfect, which is now considered the industry standard. "It certainly has a lot more power and a lot more features," said a White House data-processing expert. For those who worked in the transition, it's no problem. But for White House secretaries who are used to the IBM software, it's painful to change, and you can still find Displaywrite in some pockets of the West Wing. The computers and software in the White House mirror the trend in computer use in large organizations nationwide. PCs in the White House are increasing, now numbering about 200 despite the presence of two IBM mainframes and several smaller DEC VAX minicomputers. IBM, with a foothold, still has most of the account. But when someone, such as Sununu, wants the state of the art, IBM loses. The same is true for laptops. Grid laptops are popular in the West Wing. Nobody seems to have IBM's Convertible, which has been overwhelmed nationally by more powerful models by Grid and Compaq, or by better-priced low-end models by Toshiba, NEC and Tandy. And IBM software continues to lag. Displaywrite might have seemed fine when there was little else available, but with programs such as WordPerfect beating the IBM entry in both price and performance, Big Blue simply can't, or won't, compete. IBM has nothing to offer in the spreadsheet or database world to rival Lotus 1-2-3 or dBase. IBM is profitable, but its prospects seem shaky. Mainframes are still its mainstay but they are quickly being overtaken by desktop-size machines that can equal mainframe power at far less cost. IBM seems unable to keep up with Compaq, which beats it to market with faster, bigger machines. Compaq's machines are comparably priced with IBM's, and Compaq's reputation for quality is no less. At the low end, IBM has quality machines, but they are seldom the best buys. The company hates price competition and has always sought to dominate by distinguishing its products. In the brutally competitive PC market, that is hard to do. Brit Hume is a contributor to the Washington Post Writers Group. He is chief ABC News White House correspondent and the founding editor of a computer newsletter.