By Daniel Eran Dilger

Published: 07:15 PM EST (04:15 PM PST)

Apple has surpassed HP in both computer unit sales and revenues for the first time, taking the top spot sooner than expected on record sales of iPads. Rather than losing sales to low priced tablets, Apple said it would "continue to innovate like crazy" in the tablet arena.

Apple reported record quarterly sales of 15.4 million iPads and 5.2 million Macs, giving the company over 20 million sales of dedicated personal computing devices (distinct from its sales of more than 37 million phones). Gartner reported HP's worldwide sales for the fourth quarter to be 14.7 million, while Lenovo and Dell sold 12.9 and 11.6 million units, respectively.

Apple was expected to report sales closer to 13 million iPads, an estimate figure that was still well ahead of what Canalys had anticipated last fall when it predicted Apple would outpace HP before the second half of this year.

Both Apple's revenues and profits were twice as high as Microsoft reported for the same holiday quarter.

iPad not threatened by cheap tablets; it threatens PCs

When asked about the impact of lower priced, "content subsidized" tablets in the market, specifically Amazon's Kindle Fire, Apple's chief executive Tim cook noted that he was "really happy" with sales of iPad, pointing out that sell-through had exceeded sell-in, leaving the company with strained inventory levels in the global channel that contradict the notion that the Fire had eaten up potential iPad sales.

Cook said that Apple sees iPad as a "huge opportunity for Apple over time," reiterating the idea that the company's management believes "there will come a day when the tablet market in units is larger than the PC market.

"In fact its interesting to note that in the US, it's clear from IDC's recent data on desktops PCs that tablets exceeded desktop PC sales last quarter. You can already see different indicators that there is significant momentum in this space."

Cook on Kindle vs iPad

Cook stated that "in terms of competitiveness, the ecosystem for iPad is in a class by itself," comparing the 170,000 apps designed specifically for iPad against "just a few hundred" tablet-oriented apps for other platforms.

"I think people really want to do multiple things with their tablets. We don't really see these limited function tablets and ereaders being in same category."

Cook said other offerings "will sell a fair number of units, but I don't think that people that want an iPad will settle for limited function."

Cook added, "We're just going to continue to innovate like crazy in this area. And we think we can continue to compete with anyone that is currently shipping tablets, or that might enter in the future."

iPad eating up PC sales, not hurting Mac sales

Demand for iPads helped to blunt growth among generic PCs across the industry, with Microsoft reporting a 6 percent decline in Windows revenues for the same quarter. However, Apple's iPad sales haven't had a negative impact on the company's own Mac sales.

Instead, it appears that iPad, along with iPhone and iPod, continues to exercise a halo effect that draws customers to Apple's notebooks and desktops. The company pointed out that it had strong sales in both notebooks and with its desktop iMacs, with average weekly Mac sales being up in every geography.

Over a fifth of its Macs were sold through Apple's own retail stores, where the company reported that of the 1.1 million Macs sold to customers, half were purchased by users who were new to the Mac platform.