Audiences continue to largely tune out new reality-show concepts on the major networks this summer, with CBS dating series ”3” opening to puny ratings opposite more huge numbers for the Olympics on NBC.

According to preliminary national estimates, Olympics action including swimming, women’s diving and women’s gymnastics averaged an 11.4 rating/31 share in adults 18-49 and 35.4 million viewers overall from 7 to 11 p.m., up from the same night in Beijing four years ago; the night’s official averages will depend on start and stop times as NBC aired events well into the 11 o’clock hour. This year’s London Games continue to set the pace as the most-watched Summer Olympics on record.

CBS opened with ”60 Minutes” (0.8/3 in 18-49, 5.7 million viewers overall), followed by ”Big Brother” (1.8/5 in 18-49, 5.1 million viewers overall), which was down 10% week to week — not bad considering the tough Olympics competition. But any momentum CBS had came to a screeching halt at 9 p.m. with the series premiere of ”3” (0.5/1 in 18-49, 1.8 million viewers overall); the show had drawn a 0.8 demo rating with its special preview episode on Thursday, so Sunday’s opening score is not surprising. A repeat of ”The Mentalist” aired at 10 (0.7/2 in 18-49, 3.3 million viewers overall).

Fox, with its male-skewing comedy repeats, held up reasonably well. Following ”American Dad” (0.8/3 in 18-49, 1.6 million viewers overall) and ”The Cleveland Show” (0.9/3 in 18-49, 1.8 million viewers overall), the net aired an hour of ”The Simpsons” (1.2/4 in 18-49, 2.6 million viewers overall at 8 and 1.3/3 in 18-49, 2.6 million viewers overall) and an hour of ”Family Guy” (1.6/4 in 18-49, 3.1 million viewers overall at 9 and 1.5/4 in 18-49, 3.2 million viewers overall at 9:30). Even in its strongest category of men 18-34, though, the 6 share for Fox left it 24 shares behind NBC.

ABC had little going Sunday with encores of unscripted series ”America’s Funniest Home Videos” (0.7/2 in 18-49, 3.3 million viewers overall), ”Secret Millionaire” (0.6/2 in 18-49, 2.9 million viewers overall) and ”Extreme Makeover: Weight Loss Edition” (0.5/1 in 18-49, 1.6 million viewers overall).

Preliminary 18-49 averages for the night: NBC, 11.4/31; Fox, 1.2/3; CBS, 0.9/3; Univision, 0.9/2; ABC, 0.6/2.

In total viewers: NBC, 35.4 million; CBS, 4.0 million; Univision, 2.6 million; Fox, 2.5 million; ABC, 2.4 million.