Dr. Dre is determined to ball like a billionaire, and he moved close to that goal ... by dropping his fancy Hollywood Hills crib for big money.

Dre just scored $32.5 million for his posh pad in the exclusive bird streets hood ... which is home to Leo DiCaprio, Keanu Reeves, and a ton of other celebs. 

Dre's walking away with more than twice what he paid for it in 2011. Not bad, considering he didn't live there full time. It's not like he had to ... the Doc splurged on Tom Brady and Gisele's massive Brentwood estate for $40M last spring. 

The new owners will have plenty of space for their homies to get gangsta ... the 6-bed, 9-bath joint is tucked away on a cul-de-sac with an amazing infinity pool. 

We reached out to Dre's uber real estate broker Kurt Rappaport ... but never heard back. The home sale helps Dre creep toward billionaire status. Several estimates already have him over $650 million.