Rating information is inconsistent this week:
From Variety.com: "CW's "Smallville" achieved season highs (2.0/5 in 18-49, 4.8 million viewers overall), and "Supernatural" (1.6/4 in 18-49, 4.7 million viewers overall) was above average as well." It seems the real numbers should be around 3.7 million viewers overall.
From TVGuide.com: "With the Denver affiliates factored out, Supernatural actually dipped 330K, to 3.2 mil."
From TVbytheNumbers: "The biggest surprise of the night to me may be the improvement week over week for the CW with Smallville and Supernatural. I think we may actually see a second consecutive week with a press release about these shows. Update: there were some changes to the numbers due mostly, we’re guessing to the football game airing in the local Denver market, but even still Smallville drew 4.5 million in the final numbers." The (pre-update?) information on the site gives Supernatural 3.73 million viewers.
From EW.com: "But the night’s big story was over at the CW, where little engines that could Smallville and Supernatural quietly continue to add to their numbers. Airing at 8 p.m., the Superman show (star Tom Welling is pictured) leaped to 4.8 million (up from last week’s 4.3 million), besting its season premiere. Then, at 9 p.m., Supernatural (3.7 million) was up for the third week in a row, also earning its best ratings since September"