Unix-based server shipments slowed down during the third quarter as sales of x86 boxes rose, according to the latest numbers from Gartner.

Unit shipments dropped for Sun Microsystems and IBM, the top two vendors, though revenue increased, Gartner said. Hewlett-Packard saw both its unit shipments and its revenue for Unix servers rise, the survey said.

Overall Unix server shipments fell 6.4 percent to 103,267 units. Sun led the pack, shipping 52,038 units, but that was 12 percent fewer than a year earlier. IBM shipped 27,904 units to come in second place, representing a 12.9 percent drop in volume. It was followed by HP, which saw a 29.4 percent increase in shipments. Apple, in fourth place, shipped 4,098 units, a 33.4 percent increase. Fujitsu/Fujitsu Siemens was in fifth place.

Growing at 9.5 percent, shipments of x86 servers increased globally to 2.1 million units. HP was the top vendor, with a 30 percent market share, shipping 631,399 servers, which was a 20 percent year-over-year increase. Dell shipped 484,650 servers, a 5.4 percent increase. IBM, in third place, saw server shipments drop 3.5 percent. Fujitsu/Fujitsu Siemens and NEC followed in the fourth and fifth spots.

Though Unix server shipments fell, revenue grew 8 percent, with IBM and Sun both seeing gains in this measure, said Gartner analyst Lillian Alvarado.

IBM recorded revenue of $1.29 billion, a 5.7 percent year-over-year increase. The midrange System p servers performed better than the high-end System z servers, which suffered a strong revenue decline from last year. "IBM introduced new products in its System z line last year, and this was the reason for the large increase then," said Alvarado.

Sun Unix server revenue was $1.24 billion, a 7.3 percent increase. Sun saw especially good revenue growth from its high-end servers, according to Alvarado.

Overall, 2.2 million servers shipped worldwide during the third quarter, an 8.7 percent increase. Global server growth was driven by demand for increased capacity and growth in emerging markets, said Errol Rasit, a senior analyst at Gartner.

HP, which is still the top server vendor with a 29.3 percent market share, saw a 20.2 percent increase in shipments, followed by Dell, which saw a 5.4 percent increase. IBM was in third place, with shipments dropping 3.9 percent, followed by Sun and Fujitsu/Fujitsu Siemens.

Server revenue worldwide was $13.4 billion, a 2.6 percent increase year over year. IBM earned $4 billion, a drop of 8.1 percent from the previous year, and had market share of 30.1 percent. HP, in second place with $3.8 billion in server revenue, closed in on the top spot. The company's server revenue grew 13.9 percent, and it achieved a 28.1 percent market share. Dell was in third place, collecting $1.6 billion, a 12.6 percent increase. Sun was in fourth place, followed by Fujitsu/Fujitsu Siemens.