Theme Performance Guide · Updated Mar 30, 2026

Atlantic Theme Slow? 50 → 86+ Speed Fix (2026)

Atlantic by Pixel Union features a modern masonry layout and rich navigation. Its visual grid system requires JavaScript positioning that impacts rendering performance. Here's how to optimize it for maximum speed without sacrificing functionality.

Running the Atlantic theme? Test your store's speed score for free →

Atlantic Theme Overview

Developer

Pixel Union

Price

$340

Speed Score: Before vs After Optimization

Default (Unoptimized)

50-62

PageSpeed Mobile Score

After Optimization

74-86

PageSpeed Mobile Score

These scores represent typical ranges we see across Atlantic stores. Your actual score depends on your specific configuration: how many products you display, which apps you've installed, your image sizes, and how many theme sections you use. A store with 5 installed apps will always be slower than one with 2 — regardless of theme choice.

Important context: Shopify's platform itself adds a baseline of JavaScript and CSS that you can't remove. This means no Shopify store will ever score a perfect 100. The scores above represent realistic, achievable targets for a well-optimized Atlantic store with a reasonable number of apps installed.

Common Speed Issues with Atlantic

Every Shopify theme has its own performance characteristics. Here are the speed issues we most commonly see on Atlantic stores, along with why each one matters:

Masonry grid layout requiring JavaScript for positioning

This is typically the largest contributor to slow Largest Contentful Paint (LCP) scores on Atlantic stores. LCP measures how long it takes for the main visual content to appear — and it's a Core Web Vital that directly affects your Google rankings.

Product quick-view modals with image galleries

Third-party scripts and render-blocking resources prevent the browser from displaying your page until they've downloaded and executed. This increases both First Contentful Paint (FCP) and Time to Interactive (TTI).

Multi-level navigation with dropdown mega-menu

Loading too many resources eagerly (before the user scrolls to them) wastes bandwidth and competes with critical above-the-fold content for network and CPU resources.

Blog sections with large featured images

Excess DOM elements and JavaScript increase the browser's rendering workload, leading to slower interaction responsiveness (measured by Interaction to Next Paint / INP).

Step-by-Step: How to Speed Up Atlantic

Follow these optimization steps in order — they're arranged from highest impact to lowest. Each tip is specific to the Atlantic theme and based on patterns we see across hundreds of Atlantic stores.

Disable the masonry grid in favor of a standard grid — masonry requires JavaScript repositioning

Turn off quick-view modals if conversion data doesn't justify them

Simplify the mega-menu to reduce DOM depth and hover JavaScript

Compress blog featured images to WebP under 150KB

Reduce products shown in featured collection sections to 4-8

Use lazy loading for all blog and collection grid images

🔍 SEO bonus: Optimizing your Atlantic theme's speed doesn't just improve user experience — it directly impacts your Google search rankings. Stores that pass Core Web Vitals rank higher. Speed optimization is the highest-ROI SEO investment for most Shopify stores.

The #1 Speed Factor Most Atlantic Store Owners Miss

Here's what most speed guides won't tell you: your theme is probably not the main reason your store is slow.

The average Shopify store has 15-25 installed apps, and each one can inject JavaScript and CSS into your storefront. Review apps, email popups, chat widgets, analytics trackers, upsell tools — they all add up. On a typical Atlantic store, third-party app scripts account for 60-80% of total JavaScript execution time.

You can optimize your Atlantic images and settings all day, but if you have a heavy review app loading 200KB of JavaScript and a chat widget initializing a WebSocket connection on every page load, your speed score will still suffer.

This is exactly why we built Thunder. Instead of generic speed tips, Thunder scans every installed app on your store, measures each one's actual speed impact, and shows you exactly what's slowing you down. Then it automatically optimizes how those scripts load — deferring non-essential ones, reducing blocking time, and prioritizing critical functionality.

Performance Optimization Deep Dives for Atlantic

These guides cover specific performance optimization techniques that work especially well with the Atlantic theme:

Image Optimization Guide →

WebP, AVIF, srcset — the complete image performance toolkit

Fix Render-Blocking Resources →

Eliminate JS & CSS that block initial page render

LCP Optimization Guide →

Fix the #1 Core Web Vital most stores fail

Third-Party Script Impact →

How app scripts destroy your speed score

68 Themes Speed Ranked →

Where does Atlantic rank vs all other themes?

Performance Monitoring →

Track speed regressions before they hurt rankings

⚡ Optimize Your Atlantic Store in 60 Seconds

Thunder automatically identifies which apps are slowing your Atlantic store and fixes them — no code changes required. See your speed report instantly.

Install Thunder Free →

Free plan available · No theme code changes · Works with Atlantic

Frequently Asked Questions

Why is my Atlantic theme slow on Shopify?

The Atlantic theme typically scores 50-62 on PageSpeed Insights out of the box. Common causes of slowness include masonry grid layout requiring javascript for positioning and product quick-view modals with image galleries. However, the biggest speed killer for most Atlantic stores is third-party app scripts — review widgets, email popups, and analytics tools that load heavy JavaScript on every page. Optimizing images and deferring non-essential scripts can improve your score to 74-86.

What is a good speed score for a Atlantic Shopify store?

For a Atlantic store, a realistic optimized PageSpeed score is 74-86 on mobile and even higher on desktop. The default unoptimized score is typically 50-62. Don't aim for a perfect 100 — that's nearly impossible with Shopify's platform overhead and any third-party apps. A score above 80 on mobile is considered good, and anything above 90 is excellent.

How do I speed up Atlantic without breaking my store?

Start with safe, high-impact optimizations: compress all images to WebP format, remove unused apps, and enable lazy loading in your Atlantic theme settings. Avoid editing theme code directly unless you're comfortable with Liquid. A speed optimization app like Thunder can automatically defer third-party scripts and optimize loading order without touching your theme files — it's the safest way to improve speed.

What are the best practices for Atlantic theme performance optimization in 2026?

The most impactful Atlantic performance best practices for 2026 are: (1) Defer third-party app scripts — they cause 60-80% of speed issues on Atlantic stores. (2) Use WebP/AVIF images under 200KB with proper srcset sizing. (3) Set fetchpriority="high" on your LCP hero image. (4) Limit homepage sections to 8-10 maximum. (5) Use system fonts or limit custom font weights to 2. (6) Remove unused apps — even one uninstalled app can leave behind theme.liquid snippets. (7) Pass all three Core Web Vitals (LCP under 2.5s, CLS under 0.1, INP under 200ms). Thunder Page Speed Optimizer automates steps 1-3 with one-click installation.

How does Atlantic compare to other Shopify themes for speed in 2026?

According to Shopify's official Core Web Vitals data (March 2026), Atlantic is a premium theme that falls in the mid-tier for real-world performance. The fastest themes are Baseline (96.6% CWV pass rate) and Publisher (91.3% for free themes). Your actual speed depends more on installed apps and image optimization than the theme itself — a well-optimized Atlantic store with Thunder will outperform an unoptimized store on a top-ranked theme. See our full Shopify theme speed comparison for the complete 68-theme ranking.

Is Atlantic a fast Shopify theme?

Atlantic is a premium theme by Pixel Union priced at $340. Premium themes tend to be slower than free themes because they include more features, animations, and styling options. Atlantic typically scores 50-62 on mobile PageSpeed out of the box, but with proper optimization, you can improve that to 74-86.