Why Is My App Slow? 10 Hidden Power Apps Performance Killers

Nothing frustrates Power Apps users more than a slow, laggy, unresponsive app. Whether your users see delays while loading screens, typing into fields, or submitting forms — the good news is this:

Most Power Apps performance problems have predictable causes — and simple fixes.
The real issue is that the performance killers are often hidden beneath formulas, connectors, or design choices that seem harmless.

In this guide, we break down the 10 hidden Power Apps performance killers you should know — and how to fix each of them.

1. Loading Too Much Data at App Start (OnStart Overload)

Many creators pack dozens of ClearCollect(), Set(), and data calls into App.OnStart. This makes the app feel slow before users even see the first screen.

Why it slows your app:
 

• Fetching large datasets at startup increases load times
• Users wait longer before interacting
• Mobile devices struggle with memory-heavy loads

Fix it:

• Move non-essential loading to screen-level
• Load data on demand instead of upfront
• Only preload small lookup tables

2. Using Non-Delegable Queries Without Realizing It

Delegation issues are the MOST common cause of slow and inaccurate apps.

Symptoms:
 

• Only the first 500 or 2000 records load
• Filtering takes too long
• Galleries show incomplete results

Why it slows your app:

Power Apps pulls data locally instead of letting the data source process it.

Fix it:

• Use delegable functions like Filter(), Sort(), StartsWith()
• Avoid functions like Len(), Left(), CountIf() on large datasets
• Switch to Dataverse or SQL for enterprise data volumes

3. Too Many Controls on One Screen

Every button, label, icon, gallery, and container increases rendering workload.

Why it slows your app:

Power Apps must recalculate & redraw every control when the screen loads.

Fix it:

• Reduce controls
• Combine repeated controls into components
• Use galleries instead of copy-pasted elements
• Keep screens below 60–80 controls if possible

4. Overusing Collections (Especially with Large Lists)

Collections are powerful — but memory-heavy.
Storing thousands of rows in a collection is a guaranteed slowdown.

Why it slows your app:
 

• Excessive RAM usage
• Increasing load time
• Complex formulas rerun on big datasets

Fix it:

1. Use collections only for:

• small lookup tables
• temporary selections

2. Never use collections to replace SharePoint/SQL queries

5. Inefficient Gallery Formulas

Galleries are the backbone of many apps — but inefficient formulas inside them cause lag.

Common mistakes:
 

• Using Filter() + non-delegable functions
• Doing lookups in every row (e.g., LookUp(Table, ID = ThisItem.ID))
• Complex Visible formulas

Fix it:

• Pre-calc values before the gallery
• Use simple expressions inside gallery controls
• Turn on DelayItemLoading

Most performance problems come down to fundamentals many makers never learn properly. Investing time in focused Power Apps Course helps you design faster apps from the start instead of fixing them later.

6. Embedded Media (Images, Videos, PDFs)

Large images and videos drastically slow apps, especially on mobile.

Fix it:

• Compress all media
• Use SVG icons instead of PNGs
• Store videos in SharePoint or external links — not inside the app file

7. Multiple Patch Calls Instead of Batch Updates

Calling Patch() repeatedly — especially inside loops — kills performance.

Fix it:

• Batch updates using ForAll + Patch
• Use a single Patch for multiple fields
• Write data only when necessary

8. Overusing Timer Controls, OnVisible Logic, and Repeated Formulas

Timers and repeated formulas run continuously and consume memory.

Fix it:

• Disable timers unless required
• Move repeated calculations into variables
• Use With() to optimize complex logic

9. Using the Wrong Data Source for the Job

Not all data sources are created equal.

Typical misalignments:
 

• Using SharePoint for complex relational data
• Using Excel as a backend (very slow!)
• Using SQL without proper indexing

Fix it:

10. No Performance Monitoring or Troubleshooting

Power Apps includes a powerful tool — Monitor — that most makers underuse.

Fix it:

Use Monitor to identify:

• Slow API calls
• Delegation issues
• Repeating queries
• Long-running formulas
• Errors and warnings

Optimization starts with visibility.

Final Thoughts

Most slow Power Apps don’t need a rebuild — they just need smart optimization. By avoiding these hidden performance killers, you can dramatically improve:

• Load times
• User experience
• Reliability
• Adoption
• App scalability

A fast app doesn’t just perform better — it creates trust and drives organisation-wide usage.

Editor’s Note

If you want to master building fast, scalable, enterprise-ready Power Apps, our Power Apps and Power Automate (On-Cloud BI & Automation) program teaches everything you need to know — from delegation to Dataverse modeling to workflow automation.

• It’s practical.
• It’s project-driven.
• It’s designed for professionals who want to build real apps used by real teams.
   

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