The big unknown is what will happen to notebook sales during the holiday season. Analysts have noted sluggishness in U.S. corporate PC sales this fall as well as home sales, where most demand is for ultra-low-priced notebooks.

"The impact will come this quarter. People will be looking for cheaper products. . . . They will not be spending as much as they did a year ago," IDC's Minton said.

Intel yesterday that it was seeing significantly weaker demand across its entire product line and dropped its revenue forecast for the fourth quarter by $1 billion. 

The brunt of the slowdown in IT spending will hit servers and PCs, predicts Forrester Research analyst Andrew Bartels. Forrester is adjusting its IT spending forecast for 2009 downward, and plans to release new numbers after Thanksgiving, he adds.

"PCs and servers may see declines similar to 2001, but we're not going to be seeing that across the whole tech industry," Bartels says. "Software is a bright spot. Much of software spending comes in the form of maintenance and subscriptions. The licensing part may go down, but that's only a quarter of total software revenues."