“I just bought a new phone, so why does it already feel slow?” “I only just upgraded, and it’s freezing!”

When you’ve paid for a newer model, laggy performance is seriously frustrating. But there’s a catch: a brand-new phone can feel slow for reasons that are specific to new-device setup.

In this article, we’ll walk through six reasons a new phone can be slow or freeze, plus easy fixes you can try yourself on iPhone and Android. This information is current as of March 2026.

New Phone Running Slow? First, Know About the “Slow at First” Phase

Here’s the thing: it’s normal for a new phone to feel heavier for the first few days. If you don’t know that, it’s easy to panic and think you got a defective device, but in many cases it’s temporary.

That’s because your phone may be doing all of this in the background:

  • Finishing data transfer tasks: After moving photos, apps, contacts, and other data from your old phone, optimization can keep running in the background
  • Updating apps in bulk: Right after migration, lots of apps may update at once, using bandwidth and CPU power
  • Building the search index: On iPhone, Spotlight may need to rebuild its search index from scratch, which can take several hours to about a day in the background

In other words, the right move is often to wait 2 to 3 days after buying the phone. Leave it connected to Wi-Fi overnight, and there’s a good chance it’ll feel much faster by morning.

Still Slow? 6 Reasons a New Phone Freezes

If you’ve waited a few days and nothing has improved, check the following causes in order.

Cause 1: You Don’t Have Enough Free Storage

According to Google’s official help page, performance problems can happen when available storage drops below 10% of total storage.

If you transferred all your photos and videos from your old phone, your new phone can fill up right away. This is especially easy to run into on 64GB models.

How to check:

  • iPhone: “Settings” → “General” → “iPhone Storage”
  • Android: “Settings” → “Storage”

Cause 2: Too Many Apps Are Running in the Background

Your phone’s memory, or RAM, is like the size of your desk. If too many apps are left open, the desk gets crowded and there’s no room for new work.

When apps from your old phone are copied over during setup, unused apps may still run in the background and put pressure on memory.

Cause 3: The OS or Apps Are Out of Date

Even if the phone is new, the OS version installed at the factory may not be the latest one. Apple’s official support page also recommends updating software first when an iPhone is running slowly.

OS updates include bug fixes and performance improvements, so one of the first things to do after buying a phone is update it to the latest version.

Cause 4: An Old App You Migrated Doesn’t Work Well With the New OS

Some apps copied over from your old phone may not fully support the newer OS version. Apps like these can sometimes cause freezing, crashes, or forced closes.

On Android in particular, manufacturer-specific apps and older games are common troublemakers.

Cause 5: Animations and Visual Effects Are Too Heavy

Screen transitions and the smooth animations you see when opening apps actually use a decent amount of CPU power. On entry-level phones, meaning lower-priced models, those animations alone can be enough to make the phone feel sluggish.

Cause 6: A Defect in the Device Itself

If you’ve tried everything here and the phone still doesn’t improve, unfortunately there may be an initial defect, meaning a hardware problem with the device itself.

If it hasn’t been long since purchase, the manufacturer’s warranty may cover a free replacement. For iPhone, contact Apple Support. For Android, contact your manufacturer’s support team. If you bought the phone from a carrier, taking it to the store where you bought it is usually the safest route.

For iPhone: What to Do When It’s Slow or Freezing

Here are the most effective iPhone fixes, roughly in the order you should try them.

Fix 1: Restart Your iPhone

Start with the basics. Turn the phone completely off, wait 10 seconds, then turn it back on. A simple restart often clears temporary memory pressure and minor bugs.

  • iPhone X or later: Press and hold the side button and either volume button → “slide to power off”
  • iPhone SE (3rd generation): Press and hold the side button → “slide to power off”

Fix 2: Update iOS to the Latest Version

Go to “Settings” → “General” → “Software Update” and check whether an update is available. Your phone may feel temporarily slower during the update, so it’s best to do it before bed while connected to Wi-Fi and charging.

Fix 3: Reset the Spotlight Search Index

Go to “Settings” → “Siri & Search,” turn off search access for all apps once, then turn it back on after a few minutes. This can rebuild the index and help background processing finish sooner.

Fix 4: Delete Apps You Don’t Need

Apps you don’t use still take up storage, and they may also use resources through background activity and push notifications. Press and hold an app icon, then choose “Delete App” to clean things up.

For Android: What to Do When It’s Slow or Freezing

These fixes are for Android phones. Menu names vary a little by manufacturer, but the basic idea is the same.

Fix 1: Restart Your Phone

Press and hold the power button, then choose “Restart.” Google’s official help page also lists restarting as the first step for a frozen device.

Fix 2: Clear the Cache

You may be able to clear cached data in bulk from “Settings” → “Storage” → “Cached data,” though the steps vary by model. To clear an individual app’s cache, go to “Settings” → “Apps” → select the app → “Storage” → “Clear cache.”

Fix 3: Use Safe Mode to Narrow Down the Cause

When you start Android in Safe Mode, apps other than preinstalled ones are disabled. If the phone runs smoothly in Safe Mode, an app you installed later is probably the cause.

  • How to enter Safe Mode: Press and hold the power button → press and hold “Power off” → tap “Safe mode”

Fix 4: Turn Off Animations in Developer Options

This is a lesser-known trick. Go to “Settings” → “About phone” → tap “Build number” 7 times to enable “Developer options.”

Then set “Window animation scale,” “Transition animation scale,” and “Animator duration scale” to “0.5x” or “Off”. This can make the phone feel noticeably faster.

Still Not Fixed? Last Resort and How to Spot a Defect

If none of the fixes above work, here’s the last-resort option and how to tell whether the device may be defective.

Last Resort: Factory Reset

Make sure you back up your data first. If the phone still freezes after a factory reset with nothing installed, there’s likely a hardware issue.

  • iPhone: “Settings” → “General” → “Transfer or Reset iPhone” → “Erase All Content and Settings”
  • Android: “Settings” → “System” → “Reset options” → “Erase all data”

How to Get a Defective Phone Replaced

You may qualify for a free replacement or repair if the following conditions apply:

  • It’s within 1 year of purchase, meaning it’s still under the manufacturer’s warranty
  • There’s no physical damage, such as drops or water damage
  • The manufacturer confirms it as an initial defect

If you bought the phone through a carrier such as docomo, au, SoftBank, or Rakuten Mobile, starting with the store where you purchased it is usually the smoothest option. If you bought an unlocked phone online, contact the manufacturer’s official support team.

FAQ

How many days does it take for a new phone to stop feeling slow?

Slowness right after data transfer usually clears up within 2 to 3 days. If you leave the phone connected to Wi-Fi overnight, background processing often finishes and the phone feels much smoother. If it still hasn’t improved after more than 3 days, try the fixes in this article.

Will Safe Mode delete my data?

No, it won’t. Safe Mode only temporarily disables third-party apps. It doesn’t delete your data. Restarting normally will exit Safe Mode.

Is it okay to factory reset a phone I just bought?

Yes. It simply returns the phone to a clean, pre-transfer state and won’t harm the device itself. However, photos, apps, settings, and other data will be erased, so always back up first.

Can Developer Options break my phone?

Changing animation speed is generally safe. If you’re worried, turn “Developer options” itself back off and the settings will return to their defaults.

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