Sun Microsystems is delaying the launch of a faster version of its UltraSparc IV+ processor until sometime in the next quarter.

The 1.8GHz version of the chip was to have appeared this quarter but will now be delayed, said David Yen, executive vice-president of Sun's Scalable Systems Group, at a company event in Tokyo.

"We are postponing the introduction of the next speed enhancement. but it's coming," he said. "Next quarter we'll move from 1.5 to 1.8 GHz and later this year push beyond that."

Yen didn't detail future speed increases for the chip but when it was first announced in 2004, the company talked about a 2GHz version.

It's not the first time the 1.8GHz version of the chip, which will be used in several models of Sun hardware, has been delayed. At the 2004 announcement Sun said it would launch as a 1.8GHz chip, but when the first UltraSparc IVs arrived in September last year they had 1.5GHz clock speed.

Yen didn't specify a reason for the delay but the announcement followed news that Sun has finally caught up with demand for the 1.5GHz version of the chip. Shipments of UltraSparc IV+ processors in the last quarter were more than double those of the quarter before and will double again in the current quarter, he said.

"Supply has finally caught up and any UltraSparc you order in this quarter will get delivered in this quarter," said Yen.

The company also provided an update on its Solaris 10 operating system. The software shipped last year in an open source version and Sun said there have been 4.5 million registered software downloads.

"Since Solaris 10 we've seen growth in interest in Solaris worldwide," said Sun Chief Technical Officer Greg Papadopoulos. "It's been nothing short of phenomenal."

He said most of the Intel and AMD installations being done on servers from IBM, Hewlett-Packard and Dell.