Why Your Power App is Slow and How to Fix It

2024-11-01

Your Power App is slow. You know it, your users know it, and everyone just accepts it as a fact of life. "Power Apps are just slow, right?" Wrong. Power Apps can be fast, but most people build them in ways that guarantee terrible performance.

I've spent way too much time debugging slow Power Apps, and the patterns are always the same. People load too much data, they write inefficient formulas, they pile on controls and media without thinking about the cost. Then they wonder why their app takes ten seconds to load and stutters when you scroll.

The good news is that performance isn't magic. There are specific, fixable reasons why your app is slow, and once you know what to look for, you can make huge improvements. This isn't about switching to some expensive enterprise tier or rewriting everything. It's about understanding what actually impacts performance and making smarter choices.

The data problem that everyone has

The single biggest performance killer in Power Apps is how people handle data. They write something like ClearCollect(AllOrders, Orders) and pull down every single order in the database. Thousands of records, dozens of columns, way more data than anyone needs. Then they wonder why their app takes forever to load.

The fundamental issue is that Power Apps has to send a request to your data source, wait for the response, transfer all that data over the network, and then process it. If you're pulling down 5,000 records when you only need to show 20, you're wasting a massive amount of time and resources.

The fix is delegation and filtering. Instead of loading everything, only load what you actually need. If you're showing a gallery of the most recent 20 orders, write your formula to only request those 20 records. Use First or Filter with proper delegation so the data source does the heavy lifting, not your app.

Delegation is where Power Apps tells your data source (like SharePoint or Dataverse) to filter and sort the data before sending it. This is way faster than pulling everything and filtering it client-side. But delegation has limits. Not all data sources support all operations, and you need to write your formulas in ways that can be delegated.

The yellow warning triangle in Power Apps tells you when something isn't being delegated. Don't ignore it. That warning means your app is probably loading way more data than necessary and filtering it locally, which is slow. Rewrite the formula to be delegation-friendly, or accept that you'll have performance issues.

Another huge mistake is loading data you don't need yet. If you have a multi-screen app, don't load all the data for every screen in OnStart. Load data when the user navigates to the screen that needs it. Yes, there might be a brief delay when they open that screen, but it's better than making everyone wait 15 seconds on app start for data they might never use.

Also, be selective about columns. If you're showing a gallery of customer names, don't pull down their full address, phone number, email, order history, and 20 other fields. Just get the name and maybe an ID. You can always load more details when someone clicks on a specific customer. Loading unnecessary columns multiplies your data transfer time for no benefit.

Formula optimization that actually matters

Power Apps formulas can get complicated fast, and inefficient formulas will wreck your performance. The app has to recalculate formulas constantly as data changes and users interact with controls. If your formulas are slow, every interaction becomes sluggish.

The worst offender is redundant calculations. I see formulas like Filter(Filter(Filter(Collection, Condition1), Condition2), Condition3) where someone is filtering the same data multiple times. Every filter operation costs performance. Combine your conditions into a single filter operation: Filter(Collection, Condition1 && Condition2 && Condition3).

Another common issue is putting complex formulas directly in control properties. If you have a complicated calculation in the Text property of a label, and that label is inside a gallery showing 50 items, Power Apps has to run that calculation 50 times. Instead, do the calculation once using Set or UpdateContext to store the result in a variable, then just reference the variable in your controls.

Context variables and global variables are your friends for performance. When you need to use the same calculated value in multiple places, calculate it once and store it in a variable. Don't make Power Apps recalculate the same thing over and over. This seems obvious, but you'd be surprised how many apps I see that recalculate the same date formatting or filtering operation dozens of times per screen.

Also watch out for lookups inside galleries. If each item in your gallery does a LookUp to another data source, and you have 50 items, that's 50 separate data source queries. This is incredibly slow. Instead, load the related data once before displaying the gallery, or use proper relationships in your data model so you can get everything in a single query.

The Concurrent function can help with performance when you need to load multiple collections or run multiple operations. Instead of running them sequentially, Concurrent runs them in parallel. But be careful not to overuse it. If you're running ten concurrent operations that all hit the same data source, you might actually make things slower by overwhelming the connection. Use it for truly independent operations.

The SVG and icon performance problem nobody talks about

Here's something most Power Apps developers don't realize: icons and SVGs can tank your performance if you implement them wrong. SVG is great because it's vector-based and scales perfectly, but SVG files are actually just text (XML code), and Power Apps has to parse and render that code.

Every SVG icon in your app is code that needs to be processed. If you have 30 icons on a screen, that's 30 separate chunks of SVG code being parsed and rendered. This adds up, especially on lower-powered devices or when you have complex SVGs with lots of paths and shapes.

The solution is optimization. Most SVG files include metadata, comments, and unnecessary attributes that bloat the file size without adding any visual value. A clean, optimized SVG might be 500 bytes, while an unoptimized version of the same icon could be 2-3 KB. Multiply that by 30 icons and you're looking at significant overhead.

This is why PowerIcons automatically optimizes SVGs. The icons you copy from PowerIcons have already been cleaned of metadata, unnecessary attributes, and redundant code. The SVG markup is as minimal as possible while still rendering correctly. This makes a real difference when you're using dozens of icons.

But even with optimized SVGs, you need to be smart about icon usage. Don't put 50 icons on a single screen just because you can. Every icon has a rendering cost. Think about what's actually necessary and remove anything that's just decorative. If an icon isn't helping users understand or navigate your app, it's just slowing things down.

Also consider the complexity of the icons themselves. Simple icons with a few paths render faster than complex icons with gradients, masks, and dozens of paths. Stick with simple, clean icon designs. They look better anyway and they're faster.

One trick I use: for icons that appear multiple times (like repeated items in a gallery), see if you can reduce the number of unique icons. If every item in a 50-item gallery has a different icon, that's 50 SVG parsing operations. But if they all use the same icon, Power Apps can potentially optimize that. This isn't always practical, but it's worth considering for high-frequency elements.

Control count and when to use galleries

Power Apps has to manage every control on a screen. Each control has properties, formulas, styles, and behavior that need to be tracked. The more controls you have, the more overhead you're adding. A screen with 200 controls will be noticeably slower than a screen with 50 controls.

The biggest mistake is using individual controls when you should be using a gallery. If you're displaying a list of items, don't create 20 separate label controls. Use a gallery with one set of controls that gets repeated for each item. Galleries are optimized for this use case and will always be faster than individual controls.

I've seen apps where someone literally copy-pasted the same control layout 30 times to show 30 items. This is performance suicide. Each control is tracked separately, and all the formulas run separately. A gallery with a single template that repeats 30 times is massively more efficient.

Also clean up controls you're not using. It's tempting to just hide controls instead of deleting them, but hidden controls still exist and still impact performance. If you're not using a control, delete it. Don't just set Visible to false and leave it there forever.

Containers can help with performance if used right. You can show or hide entire groups of controls at once, which is more efficient than showing/hiding them individually. But containers also add overhead, so don't nest them unnecessarily. Keep your component tree as flat as reasonable.

Images and media optimization

Images are usually the heaviest assets in any app. A single unoptimized photo can be several megabytes, and if you have multiple images on a screen, you're forcing users to download huge amounts of data before they can use your app.

Always compress images before adding them to Power Apps. Don't upload a 5 MB photo and then display it at 200x200 pixels. Resize and compress it to exactly the size you need. There are free tools online that can compress images by 70-80% without visible quality loss.

Also be strategic about when images load. If you have a gallery of items with thumbnails, consider lazy loading the images as the user scrolls rather than loading all of them upfront. Power Apps doesn't do this automatically for all scenarios, so you might need to get creative with your formulas to control when images are requested.

For icons, this is where SVG really shines. An SVG icon might be 500 bytes, while a PNG version of the same icon could be 5-10 KB. Over dozens of icons, SVG is dramatically lighter. Plus SVG scales perfectly, so you don't need multiple sizes. One SVG works at any dimension.

If you're loading images from a external source (like SharePoint or a URL), be aware that each image is a separate HTTP request. Too many simultaneous requests can slow things down. Consider whether you really need images for every item, or if icons and text might be sufficient for most cases.

OnStart and app initialization

The OnStart formula runs every time someone opens your app, and it's often where people stuff everything they think might be needed. Then they wonder why their app takes 20 seconds to launch.

Your OnStart should be minimal. Load only the data and variables that are absolutely critical for the first screen. Everything else can be loaded later when needed. Yes, this means there might be small delays when users navigate to other screens, but spreading the load out is better than making everyone wait forever upfront.

One pattern that works well is a lightweight loading screen. OnStart sets up the bare minimum, navigates to a loading screen with a progress indicator, and then uses a Timer control to kick off additional loading in the background. This gives users immediate feedback that the app is working, even if everything isn't loaded yet.

Also avoid complex calculations in OnStart. If you need to process data, see if you can do it at the data source level instead. Or cache processed data somewhere and load the cached version instead of recalculating every time.

Collection management and memory

Collections are great for storing data in memory, but they also consume memory. If you load huge collections and keep them in memory for the entire session, you're using up resources that could be needed elsewhere.

Only keep collections that you're actively using. When you're done with a collection, clear it with Clear(CollectionName). This frees up memory and improves performance, especially on mobile devices with limited resources.

Also be smart about what you store in collections. Don't duplicate data unnecessarily. If you already have a data source connection, do you really need to also copy that data into a collection? Sometimes yes (for offline scenarios or when you need to modify data before saving), but often people create collections just out of habit without a good reason.

When you do need collections, populate them efficiently. Use ClearCollect instead of Clear followed by Collect, because it does both operations in one step. And use Collect(Collection, Table) to add multiple records at once instead of using Collect in a loop, which is dramatically slower.

Testing and monitoring performance

The only way to know if your optimizations actually work is to test with realistic data and realistic conditions. Don't just test with 10 sample records. Load 1,000 records and see how your app performs. Test on an actual phone, not just your desktop. Test with a slow internet connection, not just your office WiFi.

Power Apps has a Monitor tool that shows you exactly what's happening under the hood. Every data source query, every formula calculation, every operation is logged with timing information. Use it. If you see a query taking three seconds, that's a problem you need to fix.

Look for patterns in the Monitor tool. Are you seeing the same query run multiple times when it should only run once? That's a sign of inefficient formulas. Are you loading data that never gets used? That's wasted performance. The Monitor tool shows you the truth about what your app is actually doing.

Also pay attention to throttling. If you're hitting your data source too frequently, you might get throttled, which introduces artificial delays. Spread out your data requests, cache data when possible, and avoid polling data sources constantly for updates unless you really need real-time data.

The PowerIcons performance advantage

This brings me back to icons and why PowerIcons exists. When you use PowerIcons, you're getting optimized SVG code that's been stripped of everything unnecessary. The icons are small, clean, and render fast. This matters more than you'd think when you're using dozens of icons across your app.

Compare that to grabbing random SVG files from the internet. Those files often include editor metadata, comments, unnecessary groupings, and redundant attributes. They might be 5-10x larger than necessary. Every byte you eliminate improves performance, especially on mobile connections.

PowerIcons also gives you consistent sizing and formatting, which means you're not accidentally using wildly different icon configurations that might render differently. Consistency isn't just visual, it's also performance. When all your icons are formatted the same way, Power Apps can potentially optimize how it handles them.

Performance is a feature

Here's the reality: users don't care how your app works internally. They don't care about your data model or your formula complexity. They care about whether the app is fast or slow. If it's slow, they hate using it, even if it has all the features they need.

Performance is a user experience feature, just like good design or intuitive navigation. A fast app feels professional and polished. A slow app feels broken, even when everything technically works.

The good news is that most performance problems are fixable. You don't need to rebuild everything or become a performance expert. You just need to understand the common issues and address them systematically. Load less data, write cleaner formulas, optimize your media, and reduce unnecessary complexity.

Start with the low-hanging fruit. If you're loading 10,000 records when you only show 20, fix that first. If you have uncompressed images, compress them. If you have redundant formulas, consolidate them. Each small improvement adds up to a noticeably faster app.

And when you're adding icons and other UI elements, use tools that are already optimized for performance. PowerIcons is built specifically to generate fast, clean code for Power Apps. It's one less thing you have to worry about when you're trying to build a responsive app.

Performance optimization isn't a one-time task. It's something you need to keep in mind throughout development. Every time you add a feature, every time you load more data, every time you create a new screen, think about the performance impact. Make the fast choice when you can, and you'll end up with an app that people actually enjoy using.

Your Power App doesn't have to be slow. Most slow apps are slow because of fixable mistakes, not fundamental platform limitations. Identify the bottlenecks, fix them one by one, and watch your app transform from sluggish to snappy. Your users will notice, even if they don't say anything. They'll just use the app more because it's finally not painful.