SANTA CLARA — As promised, the 49ers are creating a new kind of history for themselves at Levi’s Stadium, though so far not quite how they intended.

OK, a clearer way to say it: The relatively tranquil Levi’s atmosphere is creating its own reputation each time the midfield stands are half-empty for most of the third quarter.

This is not rowdy, earthy, muddy, title-consecrated Candlestick Park — where the 49ers were 19-4-1 in the stadium’s final three regular seasons before moving to Levi’s this season.

(Oh yes, that includes a 3-0 Candlestick record against Seattle during that period.)

And this is absolutely not frenzied CenturyLink Field in Seattle — where the Seahawks have won 22 of their last 24 regular- and postseason games, including three straight over the 49ers.

This is the 49ers’ new $1.3 billion money machine full of cozy clubs and other gadgety hideaways for spectators.

That’s the setup for this huge Thanksgiving night showdown against Seattle, a prime-time holiday stage 49ers ownership badly wanted.

The matchup creates its own intensity: The 49ers and Seahawks remain bitter rivals, they’re both 7-4 and battling for playoff position behind division-leading Arizona and cannot afford to give ground to the other.

Of course, the last time these two teams played, Seattle barely held on in the NFC Championship game at CenturyLink, then won the Super Bowl easily.

This is an enormous game. It’s always an enormous game.

The simple conclusion: If Levi’s Stadium isn’t roaring and thumping for the home team in this game, it might never be the kind of thunderous home-field advantage that the 49ers endure every year in Seattle … and used to have at messy Candlestick.

The wins and losses aren’t a direct result of fan noise, of course, but currently the 49ers are 3-2 at Levi’s and have outscored opponents by only three points in those games (95-92).

Just last Sunday, the offense played drowsily and the 49ers almost lost to a Washington team that saw enough from Robert Griffin III in that struggling performance to bench him for the next game.

The 49ers also have suffered Levi’s losses to Chicago (currently 5-6) and St. Louis (4-7).

In comparison, Seattle is 5-1 at home and has outscored opponents at CenturyLink by 62 points.

By the way, the 49ers play in Seattle on Dec. 14.

“I wouldn’t say we haven’t played good — we’ve won more than we lost,” 49ers offensive coordinator Greg Roman said this week of the team’s home performance. “Certainly would’ve liked to play better.

“I don’t know that we’ve played our best football yet and certainly not at home. I definitely think there’s a little bit of an adjustment period there breaking it in.”

Yes, it’s a major oversimplification to say the 49ers would be playing better if not for the lackluster environment so far at Levi’s.

First, to be fair, the stadium is beautiful, has good sightlines, and has gotten loud occasionally this season; and Colin Kaepernick, for one, has consistently said he thinks the home atmosphere is better than it was at Candlestick.

Also, the 49ers have struggled at times on the road, too, this season.

My point isn’t so much about the exact win-loss record; it’s about Levi’s Stadium as part of the 49ers’ landscape and future.

Will opponents ever fear playing in this building? So far, no.

One significant note: This game is at night, which means that fans on the east side of the stadium won’t have to duck out of their seats to avoid the broiling sun.

Meanwhile, no 49ers player has said a negative word about the Levi’s lethargy.

Mainly the players are happy to be out of cramped Candlestick and to play games right next to their practice site.

But unquestionably the team would like to play better at home and would like more noise when they do.

It goes hand in hand — the 49ers’ problems on offense at home have given their fans no strong reason to leave the raw-bar line and get to their seats.

So there probably was some extra motivation when coach Jim Harbaugh ordered up the team’s first in-season practice at Levi’s on Tuesday.

In so many ways, these two teams are almost even: Kaepernick vs. Russell Wilson, Harbaugh vs. Pete Carroll, Seattle’s great defense vs. the 49ers’ up-and-down offense and vice versa.

The biggest gap between these two teams? The Seahawks can count on the fervor of CenturyLink, especially when the 49ers show up.

And the 49ers don’t know what to expect at Levi’s, even when they’re playing Seattle.

For more, see Tim Kawakami’s Talking Points at blogs.mercurynews.com/kawakami. Contact him at tkawakami@mercurynews.com. Follow him on Twitter at twitter.com/timkawakami.