Another two-hour installment of summer’s top-rated series, Fox’s “So You Think You Can Dance,” dominated Wednesday’s primetime ratings, while ABC’s “Wipeout” put up solid numbers as well. Repeats of crime dramas, meanwhile, aren’t performing as well as in years past, dragging down the averages for CBS and NBC.

According to preliminary nationals from Nielsen, “So You Think You Can Dance” remains a consistently solid performer for Fox, averaging a 3.3 rating/10 share in adults 18-49 and 8.7 million viewers overall from 8 to 10 p.m. — on par with its average on the same night a week ago. The show grew with each half-hour and was especially strong among adults 18-34, beating second-place ABC by about 40%.

ABC’s “Wipeout” expanded to two hours for the first time this summer, averaging a so-so 2.5/8 in 18-49 and 8.0 million viewers overall in the night’s opening hour before spiking up to a 3.3/9 in the demo and 8.8 million viewers overall from 9 to 10 o’clock. Closing out the night was one of the final episodes of crime drama “The Unusuals” (1.4/4 in 18-49, 4.7 million viewers overall).

NBC ran a distant third to kick off the night with “I’m a Celebrity, Get Me Out of Here” (1.6/5 in 18-49, 4.6 million viewers overall), followed by repeats of “Law & Order” at 9 (1.9/5 in 18-49, 4.8 million viewers overall) and 10 (1.4/4 in 18-49, 4.8 million viewers overall).

CBS, which aired all repeats, started slowly with sitcoms “The New Adventures of Old Christine” (1.0/4 in 18-49, 4.3 million viewers overall) and “Gary Unmarried” (1.0/3 in 18-49, 4.1 million viewers overall) before picking up some with “Criminal Minds” (1.6/5 in 18-49, 8.2 million viewers overall) and “CSI: NY” (1.7/5 in 18-49, 8.0 million viewers overall).

In latenight, NBC’s “The Tonight Show With Conan O’Brien” (3.2 household rating/8 share) edged out CBS’ “Late Show With David Letterman” (3.1/8) one night after Letterman had pulled ahead of O’Brien for the first time. The Peacock host reversed its six-night ratings decline, rising 10% vs. Thursday’s average.

O’Brien, meanwhile, dominated in final opening-week numbers released Thursday, delivering “The Tonight Show’s” highest-rated week in four years among adults 18-49 and topping “Late Show” by a 156% margin (2.3 to 0.9). In total viewers, the margin was 74% (6.1 million vs. 3.5 million).

Preliminary 18-49 averages for Wednesday: Fox, 3.3/10; ABC, 2.4/7; NBC, 1.7/5; CBS, 1.5/4; Univision, 1.4/4; CW, 0.5/1.

In total viewers: Fox, 8.7 million; ABC, 7.2 million; CBS, 6.8 million; NBC, 4.7 million; Univision, 3.7 million.