iPhone Xs wifi slow (half the speed of iPhone8)

Is it updated to the latest version of iOS? iOS 12.0.1 fixed this issue...

Update your iPhone, iPad, or iPod touch - Apple Support

iOS 12.0.1

iOS 12.0.1 includes bug fixes and improvements for your iPhone or iPad. This update:

• Fixes an issue where some iPhone XS devices did not immediately charge when connected to a Lightning cable
• Resolves an issue that could cause iPhone XS devices to rejoin a Wi-Fi network at 2.4GHz instead of 5GHz 👈🏻
• Restores the original position of the “.?123" key on the iPad keyboard
• Fixes an issue where subtitles may not appear in some video apps
• Addresses an issue where Bluetooth could become unavailable

For information on the security content of Apple software updates, please visit this website: https://support.apple.com/kb/HT201222 

Have you tried this?

Disable Wi-Fi Networking Services

Many users have reported that they’ve solved their issues by disabling Wi-Fi Networking under Settings > Privacy > Location Services > System Services. This only relates to your location being used for Wi-Fi Networking, so it doesn’t disable Wi-Fi.

I had the same issue with a brand new iPhone XS. I changed the iPhone's DNS and speeds were back to normal.

Set a custom DNS

You may try Google DNS. Here is how you can do this:

• Go to Settings > Wi-Fi
• Find your Wi-Fi
• Tap on the ℹ button
• Tap Configure DNS and select Manual
• Tap add Server
• Type 8.8.8.8, Google’s DNS numbers.
• Delete all other DNSs
• Tap Save
• You can undo this by selecting Automatic, if you want to do so.

Are you still restoring a backup from iCloud with new phone? (Check Apple ID - iCloud - backup.... also photos app, and if you are using message sync in iCloud open messages app too)

If so, the phone is prioritizing your backup restore over your speed test. Xs should be 2x faster with newer WiFi chipset. If it still performs like that when restore is complete have diagnostics ran through Apple support app or Apple store.

Nothing works. The only thing that seems to work is to separate the two frequencies, 2.4 GHz and 5GHz and force the iPhone to connect to the 5GHZ band. So far the connection has been steady over 120 mbps all day long.

Update to iOS 12.0.1; see my results above.

Don't know if this will work for everyone else, but I had the same issue since purchasing the XS; Just performed the iOS 12.0.1 update and that seems to have at least fixed the wifi issue. Don't get me started on the "restoring from a backup" problems. I have no doubt that the crawling wifi speeds I've had since day one are the culprit.

For most this is resolved by the iOS 12.0.1 update.

Same issue as with most people here and online. I'm on the latest update, and wifi still gets slow randomly. It's like a few posts above, paraphrasing him, LinkedIn take almost a minute or more to refresh.. Same for Instagram, Facebook, and others...really frustrating.. does not have any loading issue when connected to LTE... I get about 50Mbps wifi but it acts like 1.2Mbps..." .

Even more frustrating is I also have the well known system-wide stutter issue after a period of inactivity (on animations or scrolling), so this data loading issue means even more stutter/jitter on an already not smooth phone.

I have tested the XS against three phones side by side at home: XS, iphone 6(!!) and Pixel XL, both other phones work great on wifi, on the same apps, so I know for a fact it's not the app (even cross platform!) nor the router. It's 100% the phone.

[Edited by Host]

Josearr wrote:

How do you factory reset the phone ? Because I’m having that same issue.

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

The iphone 6s doesn't do it that on wifi. I've tested this over and over. It's not the router..... It's the XS that works fast after a reboot, but after a few min loads sites with pics and vids super slow.... Doing a search online has this effecting others as well.

It's hard to notice on normal sites, But try facebook app and go into someones's photos or instagtram pages with videos,. the videos will play, but at reduced resolution, not super clear.. Then turn off wifi and videos get clearer. You may not notice this unless you use your phone A LOT.

Hi

Turn your router off for 20 /30 seconds when it's back on go to settings on iPhone down to reset Reset network settings After reset enter your router wireless key.

Later to website check for a firmware for your make of router.

You have 14 days to return iPhone for exchange.

Cheers

Brian 🇬-1F1E7;

I have the same issue with my xsMax and my wife’s XS. My son’s ipad and iphone 7 sit about 300mbps in my back porch and the xs and max sit at 6-12 using wifi sweet spot. Absolutly terrible and now I cannot go back to my X. Working with apple support so they can gather logs but not hopeful.