Xiaomi 5G Slower Than 4G in Southampton (2026 Fix)

If your Xiaomi, Redmi or POCO phone shows a 5G connection but download speeds are slower than on 4G, videos buffer, or pages load inconsistently while you're in Southampton, this guide covers the most common fixes. A 5G icon does not guarantee faster speeds – network conditions, signal quality, and device settings all affect real-world performance.

Key Understanding

5G icon ≠ faster speeds automatically. Your phone may connect to a 5G mast, but throughput depends on signal quality, distance from the mast, network congestion, and whether your carrier uses standalone (SA) or non-standalone (NSA) 5G architecture.

Before You Start – Quick Checks

  • Run a speed test – Compare 5G and 4G in the same location to confirm 4G is actually faster.
  • Toggle Airplane Mode – Turn on for 30 seconds, then off to refresh your network registration.
  • Restart your phone – Clears temporary network glitches.
  • Test at different times – Network congestion varies by time of day.
  • Test in different locations – 5G performance can vary significantly within Southampton.

If these quick checks don't work, continue with the step-by-step guide below.

Quick Navigation

Diagnose the Issue First

Before making changes, use this quick diagnostic flow:

Quick Diagnostic Flow

  • Run a speed test on 5G and 4G in the same location – Confirm the problem exists.
  • Does 5G perform better in some areas of Southampton than others? → Likely coverage or local network conditions.
  • Is 5G slower at certain times of day? → Possible network congestion.
  • Does your phone stay connected to 5G but data transfer is slow? → Check preferred network type and band selection.
  • Did the problem start after a HyperOS update? → Settings or carrier profiles may have been reset.

Why 5G Is Slower Than 4G

  • NSA (Non-Standalone) 5G architecture – Many UK 5G deployments use the LTE core for signalling. If the 4G anchor is congested, 5G throughput can be limited. This is a network design characteristic rather than a device fault.
  • Network congestion – More users on 5G can reduce available bandwidth, especially in busy areas.
  • Signal quality – 5G performance drops off rapidly with distance. A "good" 4G signal can sometimes outperform an "OK" 5G signal.
  • Band selection – Your phone may be using low-band 5G (e.g., 700MHz) for coverage, which often provides lower throughput than mid-band 5G (3.4–3.8GHz).
  • Battery optimisation settings – In some configurations, battery saver or data saver modes can affect performance on certain Xiaomi models.
  • Carrier profile or firmware – Imported devices may have different band support or carrier configuration compared to UK/EEA variants.

Southampton-Specific Notes

Local Network Diagnosis

  • Useful test locations – Busy locations such as Southampton city centre, Westquay, and areas around the docks can be useful test points because network load may vary with user density and time of day. Testing in these areas during different times can help identify whether congestion is a factor.
  • Coverage variations – 5G availability and performance can vary between the city centre, the university areas, and the suburbs. Testing in different locations can help identify whether the issue is local or device-related.
  • If 5G is slower consistently in one part of Southampton – Try switching to 4G preferred in that area. If 4G provides more stable throughput, the issue may be related to local network conditions rather than a phone fault.
  • Test at different times – Peak hours in busy areas are more likely to produce slower 5G performance. Testing during off-peak hours can help identify whether congestion is a factor.

Step-by-Step Fixes

Step 1: Compare 5G and 4G Performance

Why this matters: Before troubleshooting, confirm that 4G is actually faster in your specific location and time.

  • Download a speed test app (Ookla Speedtest or Fast.com).
  • Run a test while on 5G.
  • Switch to 4G (LTE) preferred in Settings → SIM cards & mobile networks → Preferred network type.
  • Run the test again in the same location.
  • If 4G is significantly faster, continue with the steps below.
  • If 5G is already faster, there is no issue – your phone and network are working as expected.

Note: 5G speeds are not always faster than 4G in every location. Distance from the mast and signal quality are critical factors.

Step 2: Test at Different Locations and Times

Why this matters: If 5G is slower only in certain parts of Southampton or at certain times, the issue is likely network-related rather than a device fault.

  • Test 5G speed in different parts of Southampton (city centre, suburbs, near the university).
  • Test at different times of day (morning, afternoon, evening, late night).
  • If 5G performs well in some locations but poorly in others, the issue is local coverage or congestion – not your phone.
  • If 5G is consistently slower everywhere and at all times, continue with device troubleshooting.

Step 3: Check Preferred Network Type

Why this matters: In many cases, forcing your phone to stay on 5G can produce worse results than allowing it to fall back to 4G when the 5G connection is weak or congested.

  • Settings → SIM cards & mobile networks
  • Tap your SIM
  • Tap Preferred network type
  • Select 5G/4G/3G auto – this allows the phone to fall back to 4G when 5G is weak
  • If your Xiaomi provides a 4G/LTE preferred option, use it temporarily for comparison
  • Test speed again

Diagnostic approach: Try both 5G preferred and 4G preferred (if available) in the same location. This can help identify whether the 5G connection itself is the bottleneck or whether local network conditions are affecting throughput.

Step 4: Check Signal Quality and 5G Band

Why this matters: The specific 5G frequency band your phone is using can have a significant impact on speed. Low-band 5G (e.g., n28 at 700MHz) prioritises coverage over speed, while mid-band 5G (n78 at 3.4–3.8GHz) provides faster throughput where available.

  • Dial *#*#4636#*#* and tap Phone information.
  • If supported, check the frequency band in use during your speed test.
  • If your phone is on low-band 5G (n28), this may explain why 4G is faster – especially if you are on 4G+, which uses carrier aggregation with multiple LTE bands.
  • If your phone is on mid-band 5G (n78) and still slow, the issue is more likely congestion or carrier configuration.

Important: On some Xiaomi models and HyperOS versions, band information may not be visible in this menu. If not available, proceed to Step 5 without this information.

If this doesn't help, move to Step 5.

Step 5: Check Device and Carrier Compatibility

Why this matters: Different Xiaomi models and regional variants support different 5G bands. If your Xiaomi does not support a 5G band commonly used by your carrier in your area, this can reduce 5G availability or performance.

  • Check which 5G bands your carrier uses in your area.
  • Verify which 5G bands your Xiaomi model supports (e.g., n1, n3, n7, n8, n20, n28, n38, n41, n78).
  • Imported/China-region Xiaomi models may have different modem-band support or carrier configuration from UK/EEA variants.
  • If your device lacks support for your carrier's primary mid-band (n78) or has limited band support, this could explain slower 5G performance relative to 4G.

If this doesn't help, move to Step 6.

Step 6: Test SIM in Another 5G Phone

Why this matters: This is one of the most valuable diagnostic steps. It separates device issues from network/SIM/carrier issues quickly.

  • Insert your SIM into another 5G phone
  • Run speed tests on 5G and 4G in the same location
  • If 5G is slower than 4G on the other phone as well → The issue is with your carrier or local network conditions, not your Xiaomi
  • If 5G performs normally on the other phone → The issue is with your Xiaomi device – continue troubleshooting or contact Xiaomi support
  • If possible, test a different 5G SIM in your Xiaomi
  • If another SIM works normally, the issue may be with your account or carrier profile

If this helps identify the issue, proceed accordingly. If not, move to Step 7.

Step 7: Disable VPN, Battery Saver, Data Saver

Why this matters: VPNs can route traffic through slower servers. Battery and data optimisation settings can sometimes affect performance on certain Xiaomi models.

  • Disable VPN – Open Settings, search for VPN, and disconnect or remove any active VPN.
  • Set Battery Saver – Settings → Battery → Battery saver – Set to Balanced or Performance mode.
  • Disable Data Saver – Settings → Connections & sharing → Data usage – Toggle off Data Saver if enabled.
  • Set Private DNS to Automatic – Search Settings for Private DNS and set to Automatic.
  • Test speed again

Note: These settings are unlikely to be the primary cause of slow 5G, but disabling them can help eliminate possible factors before proceeding.

If this doesn't help, move to Step 8.

Step 8: Reset Network Settings

Why this matters: This resets Wi-Fi, mobile data, and Bluetooth settings without deleting personal data. It clears corrupted network configurations that may be affecting 5G performance.

  1. Settings → Connection & sharing (HyperOS) or Settings → Additional settings → Backup & reset (MIUI)
  2. Select Reset Wi-Fi, mobile & Bluetooth or Reset network settings
  3. Confirm the reset
  4. Restart your phone
  5. Reconnect to your mobile network and test 5G speed

Note: Resetting network settings will clear saved Wi-Fi passwords and Bluetooth devices, but will not delete photos or personal data.

If resetting network settings doesn't work, move to Step 9.

Step 9: Check for HyperOS Updates

Why this matters: Software updates can include modem firmware improvements and carrier profile updates that enhance 5G performance.

  1. Settings → About phone → Check for updates
  2. Install any available updates
  3. Restart your phone and test 5G speed

If you're already on the latest version and 5G is still slower, contact your carrier or Xiaomi support.

Contact Carrier (When Required)

Contact your carrier if:

  • 5G is consistently slower than 4G on multiple 5G phones in the same location
  • You've tried all steps above and 5G is still slower
  • There's a known network issue in Southampton
  • You need to check if your specific Xiaomi model is approved for all 5G bands on their network
  • Your account may have 5G restrictions

Carrier Support Contacts

Contact Xiaomi UK Support if:

  • 5G is slower than 4G on your Xiaomi, but other 5G phones work normally in the same location with the same SIM
  • You've tried all steps above and 5G is still slower
  • The issue persists with multiple carrier SIMs in your Xiaomi
  • You suspect a hardware fault with the 5G antenna or modem

Xiaomi UK Support

  • Xiaomi UK Support Portal: mi.com/uk/support/
  • Send feedback: Settings → Services & feedback

Final Verdict – Decision Tree

Use this decision tree to determine the most likely cause and next action:

  • 4G is faster than 5G consistently in multiple locations → Likely network congestion, band selection, or carrier configuration. Test with another 5G phone first.
  • 4G is faster than 5G only in one part of Southampton → Likely local coverage or mast configuration. Check carrier status and try 4G preferred in that area.
  • 5G performs better at certain times of day → Likely network congestion. Test during off-peak hours.
  • 5G on other phones is faster than 4G in the same location → The issue is likely your Xiaomi device – check network settings, reset, and update.
  • 5G on other phones is also slower than 4G in the same location → The issue is with your carrier or local network conditions – contact your carrier.
  • Low-band 5G (n28) is in use → Low-band 5G prioritises coverage over speed. If you are on low-band 5G and 4G+ is available, 4G+ may deliver higher throughput in that location.
  • Your Xiaomi model lacks support for your carrier's primary mid-band (n78) or has limited band support → This can explain consistently slower 5G performance. Check your device's supported bands.

Frequently Asked Questions

Why is my 5G slower than 4G on Xiaomi in Southampton?

Common causes include: network congestion in busy areas, NSA 5G relying on a congested 4G anchor, low-band 5G prioritising coverage over speed, or your Xiaomi model lacking support for your carrier's primary 5G band.

Is 5G slower than 4G normal in some locations?

Yes. In some locations, especially where 5G coverage is limited or low-band 5G is used for coverage, 4G+ (LTE with carrier aggregation) can sometimes deliver higher throughput than 5G.

Does 5G always mean faster speeds?

No. 5G can offer higher peak speeds, but actual throughput depends on signal quality, distance from the mast, network congestion, and which band your phone is using. In some locations, 4G+ may be faster than 5G.

How do I check which 5G band my Xiaomi is using?

Dial *#*#4636#*#* and tap Phone information. If supported, you can see the frequency band in use. If this information is not available on your device, proceed with other diagnostic steps.

Can Battery Saver make 5G slower?

In some configurations, battery optimisation can affect performance on certain Xiaomi models. Set Battery Saver to Balanced or Performance mode and test again to rule this out.

Why is 5G slower in Southampton city centre?

Higher user density in busy areas can cause congestion on 5G bands, reducing available throughput. Testing at different times of day can help identify this pattern. Busy locations such as Southampton city centre, Westquay, and areas around the docks can be useful test points because network load may vary with user density and time of day.

Does device region affect 5G speed on UK networks?

Imported/China-region Xiaomi models may have different modem-band support or carrier configuration from UK/EEA variants. Check the exact model variant and supported bands before assuming the phone is faulty.

Can 4G+ be faster than 5G?

Yes. 4G+ uses carrier aggregation (CA) to combine multiple LTE bands, which can sometimes deliver higher throughput than 5G, especially when 5G is using low-band spectrum or the NSA anchor is congested.

Will resetting network settings improve 5G speed?

It can help if network settings or carrier profiles were corrupted. However, it will not improve speeds caused by network congestion or local coverage conditions.

Does 5G use more battery than 4G?

In many cases, yes. 5G can consume more battery, especially in areas with weak signal. Some phones may reduce 5G performance to save battery, which can also affect speed.

Note: This guide is updated for 2026. Menu names may vary slightly between HyperOS and MIUI versions. 5G performance depends heavily on local network conditions. Always test in multiple locations and at different times before concluding that your device is faulty.

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