Following warnings by other companies in the PC supply chain, Nvidia said it expects revenue in the quarter finishing at the end of January to fall to $950 million, plus or minus 1 percent.

Analysts on average had expected revenue of $1.057 billion for the quarter, according to Thomson Reuters I/B/E/S.

World PC output has been disrupted because of a shortage of hard drives caused by catastrophic flooding last year in Thailand, the No. 2 exporter of the components.

Intel and other manufacturers in the PC supply chain have previously warned that the shortage, expected to last through the first half of 2012, would hurt their sales.

"It's tough. Everybody else has preannounced and brought their numbers down. They had to do it at some point." Sterne Agee analyst Vijay Rakesh said of Nvidia's forecast cut.

Hard drive maker Western Digital Corp, whose production lines were badly damaged by the floods, said on Monday it expects to recover to 60 percent normal production in the current quarter, 80 percent in the June quarter and be back to normal by the start of the September quarter.

Higher prices for hard drives have made it too expensive for some PC manufacturers to include separate graphics chips made by Nvidia in their computers they are building, Nvidia said in a statement.

Nvidia also said sales of its Tegra 2 processors for smartphones and tablets were declining faster than anticipated after it was launched last year. The company is currently ramping up production of its newer Tegra 3 chip.

Nvidia had previously forecast quarterly revenue of $1.066 billion, plus or minus 2 percent.

Shares of Nvidia dropped 2.9 percent in extended trade after closing up 2.36 percent at $14.94.

(Reporting By Noel Randewich in San Francisco; Editing by Tim Dobbyn and Steve Orlofsky)

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