Dell Inc reported lower-than-expected quarterly profit margins and warned that rising costs could depress future results, sending its shares down 10 percent.

While Dell earned more revenue than expected and booked 27 percent profit growth, investors zeroed in on the costs and cautious outlook.

Chief Executive Michael Dell, leading a restructuring of the company he founded, spoke of "winds of caution in certain financial customers" despite good demand overall.

Net income for its fiscal third quarter ended Nov. 2 grew to $766 million, or 34 cents per share, from $601 million, or 27 cents per share, a year ago. The gross profit margin slipped to 18.5 percent from 19.9 percent the quarter before.

"We'd like to see the expense side improve faster than it is," said Brent Bracelin, an analyst with Pacific Crest Securities who has an "outperform" rating on Dell shares. "The disappointment here is that you didn't see a follow-through of revenue upside to earnings upside."

Revenue rose 8.5 percent to $15.65 billion, topping the average analyst forecast of $15.36 billion, according to Reuters Estimates. But operating expenses surged 24 percent.

Dell booked costs of $50 million, or 2 cents per share, related to job cuts and asset disposals, plus $28 million, or 1 cent per share, for a year-long accounting audit.

"The bottom line is that people were disappointed," said Roger Kay, president of Endpoint Technologies Associates of Concord, Massachusetts. "People expected more than they got."

Revenue from servers used by businesses to run networks and corporate Web sites rose 8 percent to $1.6 billion. Revenue for data-storage systems also rose 8 percent, to $600 million.

Laptop computer revenue rose 19 percent to $4.7 billion while desktop revenue fell 1 percent to $4.8 billion.