Technical performance test of OpenCart versions 3.0.3.8, 3.0.4.1 and 4.1.0.3

OpenCartBot - 11 August 2025

We, OpenCartBot, conducted comprehensive performance testing of three OpenCart versions 3.0.3.8, 3.0.4.1, and 4.1.0.3 using synthetic tests and real network conditions. Testing included Core Web Vitals metrics analysis and comparison of behavior with and without caching. Tests were conducted on the homepage of a fresh OpenCart installation, without additional CMS configurations, without caching and compression on the server.

Summary: During tests of three OpenCart versions, it was found that 3.0.4.1 provides the best balance of speed and modernity, 3.0.3.8 has the fastest content rendering, and 4.1.0.3 demonstrates the most efficient caching and potential for the future. The difference in Core Web Vitals between versions is significant, and caching provides performance improvement up to 59%.

Tested versions:

OpenCart 3.0.3.8 (PHP 7.4.33)
OpenCart 3.0.4.1 (PHP 8.3.17)
OpenCart 4.1.0.3 (PHP 8.3.17)

Testing tools:

PageSpeed Insights
GTmetrix
Pingdom Tools (server monitoring)
WebPageTest (real network conditions)
Chrome DevTools (Core Web Vitals)

Site sizes after installation:

OpenCart 3.0.3.8 - 60.6 Mb
OpenCart 3.0.4.1 - 60.8 Mb
OpenCart 4.1.0.3 - 104.9 Mb

Online test results

OpenCart 3.0.3.8 - Desktop

OpenCart 3.0.4.1 - Desktop

OpenCart 4.1.0.3 - Desktop

OpenCart 3.0.3.8 - Mobile

OpenCart 3.0.4.1 - Mobile

OpenCart 4.1.0.3 - Mobile

OpenCart 3.0.3.8 - GTmetrix

OpenCart 3.0.4.1 - GTmetrix

OpenCart 4.1.0.3 - GTmetrix

OpenCart 3.0.3.8 - WebPageTest

OpenCart 3.0.4.1 - WebPageTest

OpenCart 4.1.0.3 - WebPageTest

OpenCart 3.0.3.8 - Pingdom

OpenCart 3.0.4.1 - Pingdom

OpenCart 4.1.0.3 - Pingdom

Below we present a comparative performance report of the three tested sites (OpenCart 3.0.3.8, OpenCart 3.0.4.1, OpenCart 4.1.0.3) based on provided WebPageTest metrics. Testing included performance measurement for both first view and repeat view. Key metrics:

Time to First Byte (TTFB) — time to first byte, shows server response delay.
Start Render — when the first pixels started to display.
First Contentful Paint (FCP) — time of appearance of first visible content (text, images).
Speed Index — how quickly the page became visually usable.
Largest Contentful Paint (LCP) — loading time of the largest visible element.
Cumulative Layout Shift (CLS) — cumulative layout shift during loading (smoothness of display).
Total Blocking Time (TBT) — total main thread blocking time (interface obstacles).
Page Weight — page weight in kilobytes.

Metrics Comparison

Metric	OpenCart 3.0.3.8	OpenCart 3.0.4.1	OpenCart 4.1.0.3
First View
TTFB	0.362 s	0.345 s	0.361 s
Start Render	1.400 s	1.500 s	1.500 s
First Contentful Paint	1.418 s	1.508 s	1.516 s
Speed Index	1.943 s	2.017 s	1.563 s
Largest Contentful Paint	1.418 s	1.508 s	1.614 s
Cumulative Layout Shift	0.001	0.001	0.001
Total Blocking Time	0.000 s	0.000 s	0.000 s
Page Weight	845 KB	850 KB	1079 KB
Repeat View
TTFB	0.308 s	0.277 s	0.306 s
Start Render	0.800 s	0.700 s	0.600 s
First Contentful Paint	0.805 s	0.703 s	0.626 s
Speed Index	1.320 s	1.218 s	0.640 s
Largest Contentful Paint	0.805 s	0.703 s	0.626 s
Cumulative Layout Shift	0	0	0
Total Blocking Time	0.000 s	0.000 s	0.000 s
Page Weight	27 KB	27 KB	33 KB

Key Findings

Time to First Byte (TTFB) for all three sites is approximately the same, fluctuating around 0.3-0.36 seconds — this is a good indicator of server response speed.
Start Render and First Contentful Paint (FCP) are approximately equal for all three, although OpenCart 3.0.3.8 and 4.1.0.3 have slightly better indicators compared to version 3.0.4.1 (start render and FCP are somewhat faster for versions 3.0.3.8 and 4.1.0.3).
Speed Index is best for OpenCart 4.1.0.3 site (1.563 s — First View, 0.64 s — Repeat View), which indicates fast visual page loading.
Largest Contentful Paint (LCP) is fastest on repeat view for version 4.1.0.3 (0.626 s), which is a positive sign for user experience.
Cumulative Layout Shift (CLS) is almost absent (0 or 0.001) for all three, which indicates layout stability during loading and absence of unexpected shifts.
Total Blocking Time (TBT) — in all cases 0 s, which indicates absence of delays in the main thread, so the interface remains responsive.
Page weight differs noticeably: OpenCart 4.1.0.3 — 1079 KB (first view), while the other two — around 845-850 KB. However, on repeat view the weight drops to ~27-33 KB due to caching.
Architectural differences: versions 3.x make more HTTP requests but have smaller resource sizes, while version 4.1.0.3 offers consolidated resources but larger overall size due to Bootstrap 5 and Font Awesome 6.

Conclusion

OpenCart 3.0.4.1 - optimal choice for production (best TTFB + modern PHP). Caching improvement is -53%.
OpenCart 3.0.3.8 - fastest content (best FCP/LCP), but uses outdated PHP 7. This version demonstrates slightly better start render time on first view compared to version 3.0.4.1, however it falls behind version 4.1.0.3 in Speed Index.
OpenCart 4.1.0.3 - promising and fast, best potential for long-term development, but needs resource optimization (best Speed Index, but +28% size). This version has the best visual loading speed indicators (Speed Index) and fastest repeat view, despite being 28% heavier in page weight, thanks to the most efficient caching (59% improvement).
All sites have excellent layout stability indicator (low CLS) and absence of blocking (TBT=0).
Caching provides 43-59% improvement.

Testing was conducted using standard OpenCart theme on servers with nginx/1.24.0. Results may vary depending on server configuration and extensions used.