Under assault by rivals, Dell ( DELL) largely held its ground in the second quarter as PC sales grew respectably, according to new industry reports. While Dell's sales largely kept pace with the industry, Acer saw booming sales worldwide and Apple ( AAPL), ( HPQ) and Gateway ( GTW) all gained share in the U.S, according to the reports. Overall, the worldwide PC market grew by 9.7%, according to IDC or 11%, according to Gartner, a rival industry research firm. The two firms' figures for the U.S. market were closer, with IDC pegging growth at 6.7% and Gartner at 6.4%. "On a worldwide basis, large vendors continued to gain share at the expense of mid-tier vendors and system builders," said Charles Smulders, a Gartner analyst, in a statement. Smulders attributed the gains by the large computer makers to price cuts. Dell, the biggest computer maker, saw sales grow slightly slower than the U.S. market but slightly faster than the worldwide market, according to both firms. The company's sales grew to nearly 10 million computers worldwide and 5.4 million in the U.S., according to IDC. Overall, the company's share stood at 19.2% worldwide and 34.2% in U.S. in the quarter, according to IDC. In the same period a year ago, Dell's share was 19% worldwide and 34% in the U.S., according to the firm. In contrast, Acer was the big winner worldwide, with sales growing 35.7% to 2.8 million computers, according to IDC. The company's share grew to 5.4% worldwide from 4.3% a year earlier, according to the research firm. However, there is some question as to whether Acer's strength is continuing. Last week, a note by Pacific Crest Securities analyst Brent Braceling said Acer's sales rose only 11% in June after rising more than 30% in eight of the last nine months.