Perhaps the 49ers truly are for real, and the Cowboys are not.

There has been no movement in the No.1 spot of The Post’s NFL Power Rankings all season, but the rest of the Top-5 has been filled with upheaval, as the Colts’ Sunday night shutdown of the Chiefs leaves only two teams without a loss entering Week 6.

The Rams and Cowboys continue to tumble after consecutive defeats while the Packers jumped four spots forward to No. 4 with their impressive showing in Dallas. The Raiders were the week’s biggest overall gainer, moving up six spots to No. 18 with their third straight win.

1. New England Patriots, 5-0 (Last week: 1):
The Pats are 5-0 for the fifth time in their history and only the second time since 2007 after holding Washington to just 220 yards of offense Sunday. Their defense impressively hasn’t allowed a touchdown pass yet, the first time any team in the pass-happy NFL has done that in five straight games since 1988. Daniel Jones gets the next chance to end that streak Thursday night.

2. San Francisco 49ers, 4-0 (3):
The Niners certainly looked prepared coming out of their bye week and deserving of their lofty ranking, moving to 4-0 for the first time since 1990 in Monday’s 31-3 pasting of the Browns. Their rising defense rattled Baker Mayfield and held Cleveland’s offense to 180 total yards to remain the only other unbeaten team in the league ahead of Sunday’s NFC West showdown with the Rams.

3. New Orleans Saints, 4-1 (4):
It’s been nothing but thumbs up since Drew Brees’ surgery and a Week 2 loss to the Rams, Might Teddy Bridgewater be able to make it 6-0 as the starter with upcoming games against Jacksonville, Chicago and Arizona ahead of the Saints’ bye week before Brees’ targeted return? Also, Michael Thomas is really good.

4. Green Bay Packers, 4-1 (8): Aaron Jones has more touchdown runs (eight) than Aaron Rodgers has TD passes (six), but that breakdown combined with a big-play defense (three picks Sunday of Dak Prescott) has provided an effective balance for the Packers, who face an NFC North test with Detroit next Monday night at Lambeau.

5. Kansas City Chiefs, 4-1 (2): Patrick Mahomes looked ordinary by his standards Sunday night in a surprising throttling by the Colts’ defense. It makes you wonder just how much the ankle he’s been hobbling around on is affecting him. The Chiefs, who play Houston this week, also had just 36 rushing yards, and their 13 points easily marked the lowest output (previously 26) since Mahomes became the starting quarterback last season.

6. Seattle Seahawks, 4-1 (6): Thursday night games often are clunkers, but Russell Wilson and the Seahawks showed they aren’t ready to concede the NFC West in a wild 30-29 comeback win over the Rams. Wilson is playing at an MVP level, with 12 TDs and no interceptions ahead of Sunday’s visit to Cleveland.

7. Buffalo Bills, 4-1 (10): Only New England has yielded fewer points than the Bills in the AFC. They nearly knocked off the Pats in Week 4 and then closed out a stingy 14-7 road win Sunday at Tennessee entering their bye week.

8. Dallas Cowboys, 3-2 (5): So it turns out the Cowboys weren’t as wonderful as their 3-0 record against bad teams made some folks believe. Missing two starting offensive tackles rarely is a workable situation, but Dak Prescott has not been particularly sharp in losses to New Orleans and Green Bay. If his play doesn’t improve this week against the winless Jets, it’ll really be time to worry.

9. Los Angeles Rams, 3-2 (7):
The Rams and their Aaron Donald-led defense have been torched the past two weeks, with 85 points allowed in losses to Tampa Bay and Seattle. It’s seriously put an early crimp in the defense of their NFC crown. L.A. could be pushed further down the NFC West standings with another loss this week against undefeated San Francisco.

10. Minnesota Vikings, 3-2 (13): Kirk Cousins and Adam Thielen got back in sync with two touchdown connections against the Giants, providing the balance coach Mike Zimmer has been searching for all season alongside dynamic running back Dalvin Cook. The Vikes face another NFC East foe this week with a home game against the Eagles.

11. Baltimore Ravens, 3-2 (11)

12. Chicago Bears, 3-2 (9)

13. Houston Texans, 3-2 (16)

14. Detroit Lions, 2-1-1 (12)

15. Philadelphia Eagles, 3-2 (17)

16. Indianapolis Colts, 3-2 (19)

17. Carolina Panthers, 3-2 (21)

18. Oakland Raiders, 3-2 (24)

19. Cleveland Browns, 2-3 (15)

20. Los Angeles Chargers, 2-3 (14)

21. Tennessee Titans, 2-3 (18)

22. Tampa Bay Buccaneers, 2-3 (20)

23. Jacksonville Jaguars, 2-3 (25)

24. Giants, 2-3 (22): Daniel Jones wasn’t going to win them all, especially without Saquon Barkley, but Sterling Shepard’s concussion puts the Giants in another tough spot in a short week before Thursday’s game against New England.

25. Atlanta Falcons, 1-4 (23)

26. Arizona Cardinals, 1-3-1 (28)

27. Denver Broncos, 1-4 (27)

28. Pittsburgh Steelers, 1-4 (26)

29. Cincinnati Bengals, 0-5 (29)

30. Jets, 0-4 (30): What a mess, even by Jets’ standards. Nine first downs, 128 total yards, with 10 sacks allowed on Sunday. Imagine how bad it would have been if Adam Gase wasn’t an offensive genius. At least Sam Darnold will be back soon, possibly this weekend against Dallas.

31. Washington Redskins, 0-5 (31)

32. Miami Dolphins, 0-4 (32)