By Neil Hughes

Published: 11:00 AM EST (08:00 AM PST)

Though desktop computers play a smaller role than notebook sales, the newly updated all-in-one iMac is expected to help push Mac sales even higher and give Apple a greater share of the PC market.

Following last year's iMac refresh, Apple saw 23.7 percent sequential growth. Analyst Maynard Um with UBS expects to see a similar bump in sales this year from the newly updated iMac line.

"Apple continues to provide more value," he said, noting that the four basic iMac configurations held their same prices with improved internal hardware, "and we expect it to continue to gain share in the PC market."

As noted last week by AppleInsider, Tuesday's iMac update comes at a crucial time for the all-in-one desktop. Desktop Macs have fallen from more than 50 percent of the company's Mac shipments in 2006 to just 26 percent of total units in the second fiscal quarter of 2011.

But Mac desktop sales have also seen a significant boost when Apple issues an update for its flagship product in that category, the iMac. In Apple's first fiscal quarter of 2010, when the iMac hardware was completely redesigned with an edge-to-edge glass display, desktop sales increased by 70 percent year over year. For comparison, portable sales were up just 18 percent year over year.

Um noted that the 2011 iMac refresh comes three months before the hardware arrived in 2010. He said the earlier arrival could provide upside to his third-quarter estimate of 1.15 million units sold.



Unveiled on Tuesday, the new quad-core iMacs include the new Thunderbolt high-speed input/output port. They are also powered by Intel's latest-generation Sandy Bridge processors, and have a new high-definition FaceTime camera for video chat.

The new iMac starts at $1,199 and is up to 70 percent faster, with graphics performance up to three times that of the previous generation. It retains the same all-in-one design of its predecessor.

With a strong lineup of products, Apple has continued to gain market share in the heavily competitive PC industry. Just last week, research firm Canalys fourth-largest computer maker in the world in terms of shipments, if the iPad and other touchscreen tablets are included in the totals.