HBO has spent years looking for another hit like
Season 4 of the epic fantasy opened at 9 p.m. Sunday night averaging 6.6 million total viewers, according to Nielsen.
Those are the best numbers for HBO since 2007, when the mob drama "Sopranos" ended with 11.9 million viewers.
It's also a huge bump over the 4.4 million viewers for the season 3 premiere in 2013. "GoT" premiered in 2011 with a relatively modest 2.2 million viewers and has steadily grown its audience since.
In fact, the popularity of "Game of Thrones" caused a glitch Sunday. HBO Go, the network's streaming service, crashed due to heavy demand.
At 10 p.m., HBO premiered "Silicon Valley," a new comedy satirizing the tech industry. It averaged 2 million total viewers -- the best showing for a new HBO half-hour in nearly five years.
What did you think of the "Game of Thrones" premiere?