Now that we’re safely back from the Penny Arcade Expo, it’s time to look at the Top 25 Facebook Games list for September. August is often a popular vacation month in the United States, especially with most schools (including colleges) beginning their academic calendars either the week before or after Labor Day.

As a result, it’s not surprising to see at least half of the titles on the lists showing traffic decreases over the past month.

We’ll start by looking at the list of top 25 games by daily active users — the best way to judge a game’s core audience. Only seven of the games saw gains, and two others showed no change. The largest gain went to Zynga’s newest title ChefVille, which showed up late in August this month and is already at 7.2 million DAU. After that, FreshPlanet’s SongPop grew by 1.1 million DAU to 4.2 million. Social Point’s Dragon City continues its steady growth with 400,000 DAU, showing the third-largest traffic increase of the month.

Zynga’s The Ville, which had the largest gain for August with 7.3 million DAU, was the biggest loser this time around, dropping 3.2 million DAU in just a month. EA’s SimCity Social, which debuted on the list with 1.39 million DAU in August, has actually dropped off the list.

Now we turn to look at monthly active users, which measures a game’s overall reach on the social network. The Ville was  actually in the top spot with 12.7 million MAU, but the largest gain belonged to ChefVille with 25.5 million MAU. SongPop continues to grow steadily, up by 5.5 million MAU.

Much like last month, Zynga’s CityVille suffered the largest loss by dropping 2.1 million MAU, dropping down to the No. 5 spot with a total of 19.7 million. The second-largest traffic drop belonged to EA’s The Sims Social, which fell by 1.3 million MAU.

All data in this post comes from our traffic tracking service, AppData. Stay tuned later this week for the beginning of September’s Top 25 gainers and losers, when we look at the continued performance of games that appeared on the top 25 DAU list.