Top computer industry executives stormed Washington last week in search of liberalized export regulations for computer sales to China and other emerging markets, predicting a sharp decline in exports within months unless the government's definition of "supercomputers" is drastically revised.

Computer chip technology is advancing so rapidly that garden-variety commercial computers, even laptops, will soon be powerful enough to be covered by Commerce Department controls on "supercomputer" exports, forcing U.S. manufacturers to obtain cumbersome licenses to sell computers readily available from foreign competitors without any red tape.

"Yesterday's supercomputer is really today's laptop," Lawrence A. Weinbach, president and chief executive officer of Unisys Corp., told reporters Thursday at the start of a two-day lobbying effort.

He and other computer company chief executives then fanned out across Capitol Hill, fearing stiff resistance two weeks after a House select committee headed by Rep. Christopher Cox (R-Calif.) reported with extensive fanfare that China had obtained 600 high-performance U.S. computers and almost surely used some of them to process stolen U.S. thermonuclear warhead designs.

But the computer executives left town late Friday equally concerned about what they say is the Clinton administration's seeming reluctance to take a strong stand on their behalf, having won nothing more than a pledge from senior administration officials for action on the critical issue by the end of the month.

The administration, which supports the industry's cause, has declined to send new, liberalized export rules to Congress since a meeting with industry executives in January, having been pilloried by Republicans since then for dragging its feet in response to allegations of Chinese nuclear espionage.

"The proof is in the pudding," Ronald L. Skates, president and chief executive officer of Data General Corp., said Friday after leaving the White House. "If, by the end of the month, we haven't gotten [relief], we've got a real problem."

A senior administration official would say only that "we're looking at the issue. I think everyone recognizes what the technological trends are. And we recognize there will need to be some adjustments."

When the Commerce Department began regulating the export of high-performance computers in 1988, a license was required to sell abroad any machine operating at 12.5 MTOPS, or millions of theoretical operations per second, the standard measurement of computing speed.

By 1996, computing power had increased to the point that the government removed all export licensing requirements on all computers operating below 2,000 MTOPS and divided the world market into four tiers for export purposes.

Under those guidelines, still in effect, no licenses are required for the sale of even the most powerful supercomputers--with speeds now above 1 million MTOPS--to Tier 1 countries, which are the nation's 28 closest allies.

For sales to Tier 2 countries--106 regular trading partners such as South Korea, Poland and South Africa--licenses are required only for sales of computers operating at 10,000 MTOPS or more.

The problem is with sales to countries in Tier 3--a grouping of 50 nations thought to present weapons-proliferation risks that includes China, Russia, India and Pakistan. These countries are among the fastest-growing computer markets in the world.

Licenses are required to sell computers operating at 2,000 MTOPS or more to the military of Tier 3 nations, and U.S. computer makers must notify the government and wait 10 days before selling computers rated at 2,000 MTOPS to 7,000 MTOPS to China or any other Tier 3 country for commercial purposes.

Exports of computers rated above 7,000 MTOPS for commercial purposes require licenses.

But the regulatory scheme could melt down in August, the computer executives warned last week, when Intel Corp. starts marketing its new Pentium III Xeon chip, which operates at 1,283 MTOPS.

Computers that link two of the chips--standard, small-business e-mail servers--will have ratings of 2,566 MTOPS, meaning they will be considered supercomputers for export purposes to China and other Tier 3 countries, requiring government notification and a 10-day wait before a sale can be completed.

A machine linking eight Pentium III chips--a basic commercial machine that can be manufactured by 11 foreign competitors--would run at 10,264 MTOPS and would require an export license before it can be sold to Tier 2 and Tier 3 countries. By September, the executives said, a laptop will be offered by one U.S. manufacturer with a rating of 2,500 MTOPS, qualifying it as a supercomputer for export purposes.

"There are going to be 250,000 of these multi-processor machines sold in China next year, whether we export them or not," said Lewis E. Platt, chief executive officer of Hewlett-Packard Co. "Don't screw up a good business."

What the computer industry wants is an immediate increase in thresholds from 10,000 to 30,000 MTOPS for unlicensed computer sales to Tier 2 countries and from 2,000 to 12,300 MTOPS for unlicensed sales to Tier 3 countries.

The industry also wants Congress to waive the six-month delay before a change in MTOPS export standards can take effect so manufacturers won't find themselves at a disadvantage with foreign competitors if the administration issues new, liberalized standards by June 30.

Cox, a key player in this debate, said last week that he supports unlicensed commercial exports to China of computers with speeds up to 10,000 MTOPS because such sales are permitted to Hong Kong anyway.

But Cox said he doesn't support any change that would ease the current restriction on unlicensed sales of computers above 2,000 MTOPS to the Chinese military. He also said he would not support waiving the six-month waiting period, which was enacted last year, unless the Clinton administration commits itself to fully implementing his committee's recommendations, one of which calls for a new agreement with China guaranteeing end-use inspections of all U.S. supercomputers sold to the Chinese.

CAPTION: Lawrence Weinbach of Unisys notes need to redefine "supercomputers."