Updated from 4:43 p.m. EST

For once, the optimists on Wall Street won't be disappointed. Delivering its latest financial results,

Dell

(DELL) - Get Report

not only met Wall Street's estimates on the nose, it also gave guidance that's exactly on target with current projections for the quarter now under way. That's a rarity at a time when technology analysts routinely slash profit outlooks after earnings reports.

Yet investors, proving themselves a surly bunch who've come to take Dell's gains for granted, quickly knocked the stock off the 52-week high of $30.94 that it reached in Thursday's trading. After it released results, shares slid 88 cents, or 2.84%, to $30.06.

Dell posted fiscal third-quarter sales of $9.1 billion, up nearly 10% sequentially and 22% above year-ago levels.

Net income totaled $561 million, or 21 cents a share, in line with the upwardly revised projection Dell issued Oct. 1. Profit rose 31% from the same quarter last year.

Dell said it notched a 28% year-over-year rise in overall product shipments compared with a 2% increase for the rest of the industry.

At 9.9% of revenue, operating expenses were the lowest ever, according to the company. Dell said its operating profit of $758 million was up 39% from a year ago, helped along by cost reductions, an improved mix of products and services, and lower component costs. Operating margins rose 30 basis points sequentially.

For its fiscal fourth quarter now under way, Dell projects earnings of 23 cents a share on sales of $9.7 billion, exactly in line with Wall Street expectations. That outlook assumes sequential revenue growth of about 7%.

Profit could reach as high as 24 cents a share if the market were to grow a little faster and if Dell scores better-than-expected improvements in operating expenses and cost management, said Chief Operating Officer Kevin Rollins on the conference call.

But Dell also faces downside risks, Rollins said. As its consumer business has grown, more of its sales come from lower-margin products. Dell's consumer sales grew 32% sequentially and are up 35% over last year. But in the most recent quarter, strong growth in consumer desktop PCs put pressure on average selling prices, which slid 3% sequentially, Rollins acknowledged.

In another challenge to revenues, H-P could continue its aggressive pricing on low-end consumer goods, forcing Dell to discount its own products.

Fourth-quarter company shipments are expected to increase about 10% from the third quarter, marking a 23% gain from the year-ago period.

In its release, Dell trumpeted its new No. 1 spot in PC market share, which it achieved within the quarter by unseating H-P. "The direction of customers toward standards-based computing is obvious," said CEO Michael Dell in a prepared statement.

On the call, Rollins said the company has more than doubled the pace at which it's gaining share to about 0.7 points per quarter across its products. Rollins said each percentage point of share gain is worth an estimated $2 billion in annual revenue.

The company also said it had repurchased 13 million shares during the quarter at a cost of $594 million.