15 Tips to Speed Up Magento Open Source Performance

What Causes a Magento Site to Be Slow?

Developers can influence many internal factors to speed up a Magento Open Source store. The top reasons for Magento Open Source (Magento) performance issues include:

Insufficient hosting

Choosing the right hosting solution for your Magento website is essential for ensuring fast load times, high uptime, and secure operations. While budget hosting may save money in the short term, it often leads to slower performance, unreliable service, and security vulnerabilities, which can hurt a site’s reputation and conversion rates.

Let’s look at configuring an Amazon EC2 instance according to store size and needs. Please note that the following numbers are high-level and can vary depending on the number of attributes and level of site customization.

• For Small Stores with under 1,000 SKUs, an EC2 T3.medium instance should be sufficient, providing a 2–3 second response time under low traffic.
• For Medium Stores (1,000–10,000 SKUs), an M5.large instance can handle up to 5,000 visitors per day with 1.5–2.5 second page load times.
• For Large Stores (10,000–50,000 SKUs), more robust setups like M5.2xlarge or C5.2xlarge instances are necessary, ensuring sub-2 second response times with efficient caching and optimized database performance.

Enterprise Stores (50,000+ SKUs) will need high-end EC2 instances (C5.4xlarge or larger), Amazon Aurora with read replicas, and extensive caching to maintain under-one-second response times even with millions of visitors daily.

Insufficient Server Locations

The location of your servers plays a significant role in how quickly the website loads for customers in different regions, a primary concern for global e-commerce sites.

Hosting providers with only a single server location can cause significant latency (the time it takes for data to travel from the server to the user’s device) for customers accessing your site from a region far from the data center.

For example, if the server is located in the U.S., customers from Europe or Asia may experience delays due to the increased distance. In general, a website hosted in the U.S. can experience an average latency of 150-250ms for users in Europe and 200-300ms for users in Asia.

To solve this problem, choose a global hosting solution such as AWS or Google Cloud, which offers multiple data center locations worldwide. These solutions allow content delivery networks (CDNs) to use edge servers to reduce latency by caching content closer to users.

No CDN

Without a CDN, the server hosting your Magento website is the only source for delivering content to users worldwide. This causes high latency, particularly for users far from the server’s location.

A website without a CDN, the result is the following:

• All assets (images, CSS, JS files, etc.) must be loaded from the origin server in a single location—the further a user is from the origin server, the slower the load time due to latency.
• As the number of resources increases (such as larger product catalogs or more complex designs), page load time can skyrocket due to the limited bandwidth available from a single server.
• Slow latency can be a huge detractor to the customer experience on e-commerce websites, which typically have heavy multimedia content (e.g., product images, videos, and customer reviews). This can be a huge detractor for the customer experience, leading to unnecessarily high levels of attrition across the sales funnel.

Let’s look at an example of a website hosting the server in New York, U.S. While you can expect latency to be low for users in the U.S. when a European or Asian user visits the store, the server in New York has to deliver content across large distances, which increases response time.

Without a CDN, we can estimate average latency as:

• New York to Europe: Latency of 100-150ms on average
• New York to Asia: Latency of 200-300ms on average

Let’s assume you have a high-traffic Magento Open Source store with 500+ products and several large images per page. Without a CDN, your store can experience slowdowns, especially when users from different regions try to access product pages. This can result in delayed rendering times for those assets.

• Without a CDN, page load times can exceed 4-6 seconds, especially for product images and other dynamic content such as reviews or related products.

Improper cache management

Magento heavily relies on caching mechanisms to improve performance. These systems store content (such as HTML pages, database queries, and product details) so that it doesn’t have to be regenerated on every user request.

Improper cache management can prevent this process from working effectively, leading to slower website performance, longer server processing times, and higher resource usage.

Without full-page Caching to reduce the load on the server and improve response times, Magento must dynamically generate the entire HTML of a page for each request. This is particularly problematic for product and category pages, which can be complex and require multiple database queries. The impact on performance includes:

1. Increased Page Load Time

The server has to execute database queries and render content for each page request. This results in 4-6 seconds per page load, far above the recommended ideal page load time of 0-2 seconds.

Example: A product page with dynamic content would take several seconds to process and load without cache. Each page load would require 5–10 database queries to fetch product details, images, pricing, and customer information.

2. Excessive Database Query Count

Without caching, each product or category page would require 5–10 database queries to fetch content, which increases as the number of products grows.

Example: If 500 visitors access the same product page, the website will execute 500 x 10 = 5,000 queries to render the page, resulting in slow database responses and potential timeouts.

3. High Server Load

Every request requires fresh content generation, leading to higher CPU and memory usage.

Example: Each user request consumes 1-2 CPU cycles and 200–300 MB of RAM while rendering the page. This will increase as more users visit the website.

Overloaded theme, web content, and plugins

When a theme or web content is overloaded, it means that the site is burdened with excessive or unoptimized resources, such as:

• Large, unoptimized images and videos
• Excessive or bloated JavaScript and CSS files
• Unnecessary third-party integrations and plugins
• Complex and heavy theme structures
• Unoptimized fonts, animations, and other design elements

Images

Images, especially high-resolution product or banner images, are some of the most commonly used resources on e-commerce sites. If these images are too large, not properly compressed, or in the wrong format, they can significantly slow down page load times.

Code inefficiency

Errors and unnecessary lines lead to performance issues. While large files are an issue for all web code (e.g., JavaScript and CSS), they are particularly relevant for render-blocking resources that take longer to load (particularly on mobile).

Extensions

Too many extensions or plugins within a page introduce additional third-party scripts that can slow down the page, particularly if they are unoptimized or reliant on third-party hosting.

Poorly implemented third-party integrations and plugins

The most commonly overlooked issue is third-party plugins. Many Magento sites load third-party integrations, such as analytics tracking codes, social media widgets, live chat widgets, or advertising scripts. Each integration may require additional JavaScript files, API calls, and resources, adding to the page load. While these tools are useful, they can slow down the site if they are not implemented efficiently or if they add unnecessary overhead.

For example, in a recent Magento optimization project, we examined the implementation of 5 different third-party services: Google Analytics, Facebook Pixel, a live chat widget, a product recommendation engine, and external advertising scripts. Each of these integrations contributed to overhead, estimated as follows:

• Google Analytics: ~50 KB
• Facebook Pixel: ~30 KB
• Live chat widget: ~200 KB
• Advertising Scripts: ~150 KB
• External API calls: ~100 KB per call
• Total Overhead: 500–700 KB of additional resources just for third-party services.

In this example, scripts were loaded synchronously. They blocked the rendering of the page, increasing the time to first paint (TTFP) and time to interactive (TTI), both critical measurements of website performance. The result was an increase in page load time by 2–3 seconds or more, depending on whether external services were slow to respond or if there was network congestion.

Solution: Asynchronous Loading of Scripts (async attribute)

The async attribute allows scripts to be loaded in parallel with other resources (e.g., images and CSS) without blocking the page rendering process. When a script is loaded asynchronously, it doesn’t stop the browser from painting the page, allowing for faster initial rendering. Later on in this post, we’ll address more tips to speed up your Magento performance.

Too many redirects

Too many or long chains of redirects cause inefficiency.

Lack of mobile optimization

Page loading speed on mobile devices must be fast enough to transfer over unreliable networks and be read on small screens.

However, not all themes are responsive to mobile devices, and not all developers have created image, extension, or caching policies that reflect mobile needs.

Continue reading to see how to address these performance issues and reap the full benefits of Magento.