by , 10:45 AM EDT, April 17th, 2008

Apple's Mac market share continues to jump in the U.S., rising to 6.6% of the market, according to Gartner, which released preliminary numbers for the 1st quarter late on Thursday. The firm said that Apple's unit sales grew by 32.5%, while the U.S. market as a whole rose by just 3%. Gartner's figures show Apple with some 1.01 million Mac sales in the U.S., up from 762,000 in the same quarter of 2007.

"Gartner's early results indicate that Apple experienced the strongest growth rate among the top 5 vendors in the U.S. market," the company said in a statement. "Apple enjoyed strong retail sales, and there were indications that Apple showed decent growth in the professional market as well."

IDC also released numbers for Q1, and that company's findings showed Apple with a flat 6% of the U.S. computer market, with unit sales increase of 25.2%. According to IDC, Apple sold 950,000 Macs in the U.S., up from 759,000 in Q1 2007. The firm also pegged total U.S. unit sales growth for all PC manufacturers at 3.5%, slightly higher than Gartner.

Both firms show Apple as the #4 PC maker in the U.S., though neither place Apple in the top 5 in worldwide sales. Apple's worldwide unit sales weren't released, either. On the worldwide stage, total shipments grew by 12.3%, according to Gartner, and 14.6%, according to IDC. Both firms said that growth was fueled by portables and very low-cost PCs.

HP remains the #1 computer vendor in the world, with Dell a close second. HP's sales have remained consistently strong throughout the world, while Dell has been rebounding from a fairly miserable 2007. In the U.S. market their positions were reversed, with Dell claiming the top spot, and HP taking second.

Apple releases its own quarterly numbers on Wednesday, April 23rd, and The Mac Observer will offer extensive coverage of those results.