SAN FRANCISCO -- An analyst firm corrected its ranking of server vendors Thursday that had showed IBM (IBM) - Get Report losing its top place to Hewlett-Packard (HPQ) - Get Report.

Gartner revised its first-quarter server revenue estimates, released in May, which had given the No.1 spot to H-P for the first time. The revision restores IBM as the leader, with 29.4%, or $3.91 billion in server sales, although statistics do show that Big Blue lost 0.1% of revenue share to other vendors, year over year.

H-P took in an estimated $3.77 billion, increasing its share by 0.3% to 28.3% of total server revenue.

Dell

(DELL) - Get Report

moved up half a percent, to 12.3% of revenue share, with server sales totaling $1.64 billion.

H-P is the leader in unit shipments, with 30.1% of all servers shipped, vs. 22.7% for Dell and 13.3% for IBM. H-P's and Dell's shipments are primarily x86 servers, which typically cost well below $10,000. Gartner's server estimates include UNIX servers and mainframes, of which IBM is a leading supplier. Starting prices on mainframes range from $100,000 to $1 million, depending on model.

Dell server unit shipments grew fastest, at 15.8% year over year, compared with 7.8% for H-P and 2.3% for IBM.

"Based on updated guidance and additional analysis of the data, we have revised the revenue statistics for the first quarter of 2008," Jeffrey Hewitt, research vice president at Gartner, said in a statement.