Fast National ratings for Wednesday, August 29, 2012.
 
CBS' "Big Brother" continued its late-summer growth on Wednesday, but it was "America's Got Talent" that delivered the night's biggest ratings and carried NBC to primetime wins in most key measures.
 
Once again, with the Republican National Convention airing live in the 10 p.m. hour on all three networks, Fast National ratings are extra imprecise. 
 
For the night, NBC averaged a 1.7 rating among adults 18-49, beating FOX's 1.6 rating in the key demographic. CBS averaged a 1.4 rating, while ABC averaged a 1.0 key demo rating. The CW did a 0.4 key demo rating for Wednesday night.
 
Overall, NBC averaged an estimated 6.485 million viewers to go with a 4.3 rating/7 share for Wednesday primetime. CBS averaged a 3.4/5 and 5.01 million viewers for second, followed by FOX's 4.31 million viewers and 2.8/4. ABC was fourth with 3.4 million viewers and a 2.3/4, while The CW averaged 1.15 million viewers and a 0.7/1.
 
[Univision averaged 3.655 million viewers and a 1.5 rating among adults 18-49 for Wednesday night.]
 
8 p.m. - "Big Brother" started primetime off in first for CBS with 6.71 million viewers and a 2.3 rating among adults 18-49, both up from last week. NBC's "America's Got Talent" encore averaged 5.81 million viewers for second and a 1.4 key demo rating for third. FOX's "So You Think You Can Dance" was down from last week with 4.11 million viewers and flat with a 1.5 key demo rating. ABC's repeats of "The Middle" and "Suburgatory" averaged 4.03 million viewers and a 1.0 key demo rating. The CW's "Oh Sit!" remained strong with 1.27 million viewers and a 0.4 key demo rating.
 
9 p.m. - "America's Got Talent" delivered 9.13 million viewers and a 2.5 rating among adults 18-49 to give NBC the 9 p.m. hour. A "Criminal Minds" repeat put CBS in second overall with 5.47 million viewers and third with a 1.3 key demo rating. FOX's "So You Think You Can Dance" improved to 4.5 million viewers and a 1.6 key demo rating. ABC remained fourth with 3.57 million viewers and a 1.2 key demo rating for repeats of "Modern Family" and "Suburgatory." On The CW, a repeat of "Supernatural" averaged 1.03 million viewers and a 0.3 key demo rating.
 
10 p.m. - NBC held on to win the 10 p.m. hour with 4.52 million viewers and a 1.2 rating among adults 18-49 for the Republican National Convention. CBS' convention coverage averaged 2.84 million viewers and a 0.6 key demo rating, compared to the 2.6 million viewers and 0.7 key demo rating for ABC's coverage.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change, particularly in the case of live events.