iPhone 17 Pro Max poor data connection compared to iPhone 15

Since I moved from a 14Pro to a 17Pro, I have only problems.

Most of the time, websites, streaming, apps can't connect to the internet.

In 4G, 5G, any wifi.

Everything takes forever to load. Streaming stops after 3 minutes, you have the spinning circle (looking for internet) and then it works again for 10 minutes, and starts again.

I did everything suggested:

Reset the network settings

Reinstall iOS26 (I did both with a restore, and one out of the box without restore)

Airplane mode ON then OFF

Update Carrier settings.

Remove all VPN configs.

Delete all VPN apps.

Nothing works.

Now I know it's not my configuration since it behaves like this anywhere. In coffee shops, at work, at home, at friends, in different countries.

I have 3 different carriers, and all show the same behavior.

If it were a config problem as most people would tell you, or a hardware problem, then it would not show the same problems on my wife 17Pro, my friend's iPhones 17Pro or ProMax.

Hopefully they're going to fix this major problem in a coming patch.

Please post a screenshot of the dashboard from both devices.

You’re welcome. Just as an afterthought, have you replaced the SIM or had them reprovision your SIM cards in the 17 PM?

The split bars still indicate weak signal, which is substantiated by your Field Test. They can also indicate it may be roaming. But the test isn’t the same between the two devices.

Are both devices on and next to each other when testing? Have you tested 5G and if so what do the field tests show. Have you run the Speed Test app or equivalent in UK? If so do you have screenshots?

You don’t show the results for the other device. If you want to pursue this with Apple Syupport it’s certainly your prerogative. You want to have Apple perform diagnostics on your iPhone. It can be done in person at an Apple Retail Store or at an Apple Authorized Service Provider. You can also contact Apple Support and request remote diagnostics.

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I don’t think your graphs and tests are very scientific. Speed tests at random times as the signal measurement are meaningless. Not being connected to the same channel is a huge issue in testing. I’m not saying there isn’t an issue, just nothing you’ve shown is an equal comparison. I see flawed testing and you see a flawed device. Time to let the manufacturer run diagnostics and determine if you have a defective device. Good luck!

Look at the broken bars on the signal strength meter on 17 PM. Broken bars mean there is a weak or unstable cellular signal, or that the phone could be in a state of searching or trying to connect to the network. The dashed or broken bars visually communicate that the signal quality is not fully solid or consistent.

Let’s see the screenshots please.

I have an IPhone 17 pro and I am having the same poor network issues. I live in the United States and travel monthly for work. No matter what state or city I go the network issues slow and drops a lot. I also swapped from LTE to 5g on to 5g auto. Apple should let you downgrade phones because this issue have been a pain because I need my phone to be reliable.