NET WORTH: $1.6 billion -45%

LAST YEAR: $2.9 billion

AGE: 70

RESIDENCE: Rolling Hills

SOURCE OF WEALTH: Computer technology

THE MONEY: Computer memory-chip maker saw wealth recede from all-time high as sales at his Kingston Technology Co. fell 35 percent to $4.3 billion due to lower memory prices.

BUZZ: Press-shy billionaire lives in tony Palos Verdes Peninsula community of Rolling Hills, but is more active in Orange County. Continues to be big donor to Huntington Beach PBS affiliate KOCE-TV and UC Irvine medical school. Last summer donated $1.2 million to give iPads to first-year med students through 2015. With wife, Mary, has contributed to Democratic groups and politicians, including Rep. Loretta Sanchez, D-Garden Grove, and Tim Kaine, Virginia governor now running for a Senate seat. Tu and partner David Sun co-founded Kingston and sold it in 1996 amid PC boom for $1.5 billion. Bought it back three years later for $450 million and rebuilt company.