The Wrestling Observer Newsletter has some detailed information of the viewership for the live Smackdown that aired on 8/30 on Syfy.
The live WWE SmackDown special on SyFy did a 2.14 cable rating with 3.28 million viewers. SyFy usually averages a 0.52 rating in that timeslot on Tuesday nights with airing movies.
Natalya & Beth Phoenix vs. Alicia Fox & Kelly Kelly gained 97,000 more.
Sheamus vs. The Great Khali lost 456,000 viewers which is expected based on the unusually high growth for the contract signing.
The Christian vs. Randy Orton cage match for the World Title gained 931,000 viewers but the show had an unexpected overrun so the 931,000 would include people tuning into SyFy for the next program.
If you take the breakdown to 10pm, the growth for the main event was 278,000 viewers, bringing the final quarter rating to a 2.40 and the overrun to a 2.83.