Small firms grow, big firms struggle. (Special Edition: Taking Stock) (company profile)

Revenues for high-technology companies grew an average of 33 percent last year. That's a decent gain, unless you consider the phenomenal growth the high-tech industry experienced in the 1980s.

"If that was a wave," says Howard P. Foley, president of the Massachusetts High Technology Council, "then this is a ripple."

Forty-nine of the 80 Massachusetts high-tech companies turned a profit in 1990. Cambex Corp., based in Waltham, outperformed the industry, achieving a 91 percent return on equity. The average return on investment for profitable companies was 19 percent.

Cambex develops, manufactures, swaps and resells memory storage systems for IBM mainframe …