Outdated Magento 2 Speed Tips to Drop in 2026

The Magento 2 speed tips that no longer work in 2026 are merging JavaScript and CSS, tuning query_cache_size, cleaning Magento 1 log tables, and relying on Elasticsearch, Redis and the flat catalog. Each made sense at some point, but the platform and its infrastructure moved on, and Adobe's documentation spells out what to do instead.

Plenty of Magento speed guides were written for 2.3 or early 2.4 and have had their dates refreshed without their content. Some quote numbers with no source, or misquote the studies they do cite. This article lists the advice that still circulates, with what's true today and the replacement for each.

Which Magento speed tips are outdated?

Why is merging JavaScript and CSS a mistake now?

Merging cut request counts back when HTTP/1.1 needed a connection per file. HTTP/2 downloads many files over one connection, so merging just produces one large file for no benefit. Adobe says so directly: don't merge or bundle files if your deployment uses HTTP/2.

Built-in JS bundling is worse: it loads every bundle on the first visit, whether the page needs it or not. Adobe measured a clean-install homepage on a Slow 3G connection taking about 44 seconds to load its bundles. Use minification, HTTP/2, page-type advanced bundling, or a lighter theme such as Hyvä. How RequireJS loads files in the first place is covered in the frontend lesson (Arabic, with English code).

Why don't query_cache_size and log tables matter?

• Query cache: MySQL 8.0 removed it entirely, and MariaDB disables it by default because it doesn't scale under load. Any guide recommending query_cache_size was written for an old version.
• Log tables: names like log_url, log_visitor and dataflow_batch_export come from Magento 1. In Magento 2 the visitor_clean cron job cleans the customer_visitor table daily on its own.
• The setting sometimes called "log cleaning": MySQL Message Queue Cleanup removes messages from database-backed queues, and its defaults are sensible. It has nothing to do with page speed.

What does matter in the database is keeping tables and indexes in memory and writing collections well, covered in the database and performance lesson (Arabic).

Why are Elasticsearch, Redis and the flat catalog behind us?

• Elasticsearch: its modules have been deprecated since Magento 2.4.8, it isn't listed in the 2.4.9 requirements, and Elasticsearch 7.17 reached end of support on January 15, 2026. Use OpenSearch 3.
• Redis: Adobe's requirements for the latest 2.4.6, 2.4.7 and 2.4.8 patches mark it as not supported and list Valkey 8.1; 2.4.9 requires Valkey 9. The steps are in moving Magento from Redis to Valkey.
• Flat catalog: Adobe says it's no longer a best practice from 2.3.x, and both settings are off by default. Magento relies on index tables instead, explained in the indexers lesson (Arabic).

What goes wrong with lazy loading?

There are two opposite mistakes. One is believing Magento has no lazy loading; in fact core's listing image template outputs loading="lazy" and image dimensions. The other is lazy-loading everything, which delays the main image that determines LCP: web.dev found pages that did so had a median LCP of 3,546 ms versus 2,922 ms without.

The rule: load the main above-the-fold image immediately and lazy-load the rest.

How should you read speed statistics in articles?

• Ask for the source: figures like "every 100 ms costs 1% of sales" circulate widely without a link to an original study.
• Read the study itself: web.dev's Rakuten 24 case study reports a 53.37% increase in revenue per visitor and a 33.13% increase in conversion rate, and some articles swap the two. Tokopedia's study reports a 23% increase in average session duration, not in conversions.
• Separate lab from field: a PageSpeed score is a lab measurement, while the Core Web Vitals assessment uses real-user data at the 75th percentile.
• Know the current metrics: the Core Web Vitals are LCP, INP and CLS. TTFB is a diagnostic, and TTI was removed in Lighthouse 10 in 2023.

The full order of changes that do make a difference is in the Magento 2 speed checklist for 2026.

Checklist: audit your store's settings

• dev/js/merge_files and dev/css/merge_css_files are off if you serve HTTP/2
• The database configuration has no query_cache_size
• The search engine is OpenSearch 3, not Elasticsearch
• Cache and sessions run on Valkey at the required version
• Use Flat Catalog Category and Use Flat Catalog Product are set to No
• PHP matches the requirements table for your version
• No scripts clean Magento 1 tables
• The LCP image isn't lazy-loaded
• You measure LCP, INP and CLS from real users