"It isn't just one thing, it is multiple things," said Bozman, of the Unix server sales drop.

Bozman said it is too early to say whether the first quarter results indicate that users are accelerating a shift away from Unix.

Overall, IDC said the worldwide server market increased by 4.6% year-over-year to $10.4 billion in the first quarter.

Gartner Inc., this week put the server growth at 6% for the quarter and the total market at $10.75 billion. Both firms cited the x86 systems as key to the growth.

"It's really going to take a while to see what the shape of that will really be." Charles King, an analyst at Pund-IT Inc. in Hayward, Calif., of the broader Unix trend.