PC users in the United States are less likely to pay to download music than Apple Mac users, who are also more likely to purchase CDs, a market research firm said Wednesday.

Half of all Mac users in the third quarter paid to download tunes, compared with 16% of their PC-using counterparts, according to the NPD Group. In addition, Mac users were more likely to listen to music and watch videos on their portable media players.

"There's still a cultural divide between Apple consumers and the rest of the computing world, and that's especially apparent when it comes to the way they interact with music," NPD analyst Russ Crupnick said in a statement. "Mac users are not only more active in digital music, they are also more likely to buy CDs, which helps debunk the myth that digital music consumers stop buying music in CD format."

In its latest quarterly Digital Music Monitor report, NPD found that more than 32% of Mac users reported buying CDs in the third quarter of this year, compared with 28% of PC users. Also, 34% of Mac users had uploaded music to their MP3 players vs. 16% of PC users.

Mac users are also much more likely to listen to music files on their computers: 56% compared with 31% for PC users.

The market for digital music is growing slower than the record industry would like, especially as CD sales decline. The latest research shows that Mac users are more likely to help with the transition.

"The more consumers become comfortable paying for digital music, the more chance they will evangelize to others," Crupnick said. "And at this point in the game, it's the growing base of Apple consumers that are the industry's low-hanging fruit when it comes to converting from physical to digital music."

Apple's share of the U.S. computer market, based on unit-volume sales at U.S. retailers, is growing, rising to 9% from January through October from nearly 6% in 2006, NPD said. "Apple's growing share in the personal computing environment -- and continued success with iPod sales -- is a potential harbinger for the continued growth of digital music," Crupnick said.