Mac zigs while the PC market zags


Philip Elmer-DeWitt is a senior editor at Fortune.

Our survey of analysts suggests that Apple is set to report its first 4 million Mac quarter

In the Gartner report issued this week, U.S. sales of Apple's (aapl) Macintosh computers grew 23% year over year last quarter while overall PC sales (even including the Mac) fell 6.6%.

That's been the story for much of 2010: PC sales weak, Macintosh sales strong.

But the Mac has been on its own trajectory for some time, boosted by a steady flow of refreshed products -- iMac, MacBook, MacBook Air -- and by the magnetic pull of the iPhone, iPad and iPod touch, which keep drawing new customers into the Apple Store.

Whether that trajectory slowed or accelerated in the Christmas quarter -- usually Apple's strongest -- is one of the questions that will be answered definitively next Tuesday, when the company reports its fiscal Q1 2011 earnings.

Meanwhile, we've polled three dozen analysts for their Mac unit sales predictions. The average of their estimates -- 4.15 million, posted in the chart above -- would represent a slight diminution in the Mac's sales growth.

But there was, as usual, a sizable gap between the most optimistic estimate (4.49 million by Apple Finance Board's Alexis Cabot) and the most pessimistic (3.6 million from UBS's Maynard Um).

Below: The numbers we've gathered so far. The Deagol rating in the fourth column is a measure of each analysts accuracy over the past two or three quarters, with 1 the highest and 30 the lowest. (See here for an explanation for how it was derived.)

Further below, a chart of the breakdown between desktop and laptop unit sales over the past three years. You can see at a glance how important to Apple the MacBook line has become.

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Analyst, affiliationMac sales (millions)Date of est.Deagol rank
Alexis Cabot, Apple Finance Board4.4912/23/108
Dennis Hildebrand, Apple's Gold4.4712/28/1025
Mark Beauch, Apple Finance Board4.4512/27/10NA
Nicolae Mihalache, Traderhood4.3512/30/1030
Robert Paul Leitao, Apple Finance Board4.351/2/1111
Horace Dediu, Asymco4.3012/29/101
Jeff Fosberg, Apple Finance Board4.3012/29/1013
Turley Muller, Financial Alchemist4.3012/29/104
Daniel Tello, Deagol's AAPL Model4.3012/23/103
Patrick Smellie, Apple Finance Board4.2812/29/1024
Matthew Hoffman, Cowen & Co.4.2712/16/1033
Mark Moskowitz, J.P. Morgan4.2612/16/1032
Doug Reid, Stifel Nicholaus4.261/10/1123
Mike Abramsky, RBC Capital4.231/12/116
T. Michael Walkley, Canaccord Genuity4.201/4/1131
Shaw Wu, Kaufman Bros.4.2012/16/1034
Chris Whitmore, Deutsche Bank4.201/3/1114
Yair Reiner, Oppenheimer4.191/3/119
Gene Munster, Piper Jaffray4.1711/29/1028
Tavis McCourt, Morgan Keegan4.1612/30/1036
Bill Shope, Goldman Sachs4.1212/12/1019
Richard Gardner, Citigroup4.101/13/1121
Rajesh Ghai, Think Equity4.0911/29/1035
Charlie Wolf, Needham4.0610/19/10NA
Jeff Fidacaro, Susquehanna4.0611/29/1017
William Power, Baird4.0511/4/10NA
Ben Reitzes, Barclays Capital4.011/12/1118
Brian Marshall, Gleacher & Co.4.0112/29/1027
Hendi Susanto, Gabelli & Co.4.0012/17/10NA
Scott Craig, Merrill Lynch4.0012/9/1022
Kathryn Huberty, Morgan Stanley4.0012/29/1029
Nehal Chokshi, Technology Insights3.991/4/1110
Brian White, Ticonderoga3.961/4/11NA
William Fearnley, Janney Capital3.841/12/1115
Daniel Ernst, Hudson Square3.8012/29/1040
Maynard Um, UBS3.6012/28/1020

. . .

In Q4 2010, five analysts predicted -- incorrectly -- that Apple had just sold 4 million Macs. This time, curiously, all but five expect Apple to report sales of 4 million or more.

See also:

[Follow Philip Elmer-DeWitt on Twitter @philiped]

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