As usual, tech stocks loomed large in after-hours trading Thursday, both in volume and in big percentage moves.

Tonight's major tech showing came from Microsoft ( MSFT - Get Report), which climbed 4.8% to $30.50 in a flurry of trading after reporting fiscal third-quarter earnings that soared 53.1% year over year. The software giant reported earnings, excluding items, of $4.93 billion, or 49 cents a share on revenue that climbed 32.1% $14.4 billion. Analysts polled by Thomson Financial had sought 46 cents a share on $13.89 billion in revenue.

Baidu.com ( BIDU - Get Report) was also red hot, lately rising 19.7% to $130.87, after the Chinese Internet-search company reported 142.6% higher profits year over year to $11.1 million, or 32 cents a share. Shares of Varian Semiconductor Equipment Associates gained 15.1% to $65.62 after the Gloucester, Mass., company reported that fiscal second-quarter earnings more than doubled to $38.4 million, or 69 cents a share, and came in ahead of estimates.

Canada-based Sierra Wireless ( SWIR - Get Report) said first-quarter earnings rose sharply to 24 cents a share, double what Wall Street had expected, and Foundry Networks , of Santa Clara, Calif., posted a first-quarter top line of $135.8 million that bested targets.

A few health names were likewise rising on positive earnings, among them Quidel ( QDEL - Get Report), a San Diego-based maker of diagnostic tests for infectious diseases and reproductive health. Per-share profits slipped by a penny from last year to 14 cents, but this was still 4 cents above the mean projection. Shares gained 82 cents, or 6.1%, to $14.22, in recent late trading.

Melville, N.Y.-based OSI Pharmaceuticals was up 2.4% at $36.98 after adjusted first-quarter income from continuing operations increased dramatically from last year to 33 cents a share. Atlanta's Sciele Pharma came in above expectations, and its shares were recently up 1.2% at $25.90.

As for losers, MEMC Electronic Materials ( WFR) was among the worst sufferers, lately sinking 11% at $59.75. The Missouri-based semiconductor company edged out earnings estimates but revenue, at $440.4 million, was a hair below. Chipmaker SanDisk ( SNDK) slid 4.1% to $43.34 after swinging to a small GAAP-based loss that panned out at break-even. Non-GAAP income topped projections by 2 cents, but shares were still down $1.65, or 3.7%, to $43.55.

Communications chipmaker Broadcom ( BRCM) also moved to the downside after hours, tumbling 6.1% to $32.75 after the Irvine, Calif., company said it couldn't determine second-quarter guidance due to "mixed outlooks" from some of its larger customers. Semiconductor Conexant Systems ( CNXT), meanwhile, foresees a "core" fiscal third-quarter loss of 3 cents to 4 cents a share on sales of between $178 million and $182 million. Analysts are looking for a 2-cent per-share loss on sales of $190.7 million. Shares were off 3.3% to $1.46.

Elsewhere, Boulder, Colo.-based Dynamic Materials ( BOOM), which makes explosion-welded clad metal plates, plunged 7.6% to $34.30 after saying it expects second-quarter results similar to those of its first quarter, when two analysts are seeking a 7-cent sequential rise in profits per share. Boston's First Marblehead ( FMD), a student lender, widely missed fiscal third-quarter expectations, and Kansas-based trucker YRC Worldwide ( YRCW) chopped at least 50 cents off its 2007 earnings guidance. Full-year income is now pegged at $4 to $4.20 a share. Shares lost 5.5% to $43.22 in recent after-hours trading.