PrestaShop Extremely Slow with Thousands of Variations in Multistore: Performance Issue Despite Optimisations?

[zack24]

Hello PrestaShop community,

I am using PrestaShop 8.1.3 in multistore mode with a child theme based on the Classic theme, and I am experiencing extreme slowness, particularly on category and product pages.

👉 Context:

Some of my products have several thousand variations (combinations).

I have already implemented native caching and additional modules such as SuperSpeed.

I am using Cloudflare CDN to enhance loading speeds.

My theme is a child theme of the Classic theme, meaning it largely relies on PrestaShop’s default structure.

Despite these optimisations, my site remains very slow, especially on category and product pages.

📌 My questions:

Does PrestaShop handle thousands of variations in multistore mode well, or could this be causing the slowdown?

Are there specific optimisations to improve performance with a large number of variations? (Database optimisation, indexing, server configuration, recommended modules, etc.)

Could using a child theme of the Classic theme impact performance and slow down my site?

I would really appreciate any insights and suggestions! 🚀

[ps8modules]

Hi.

If you have thousands of combinations for one product, there will be millions for all products.

How to reduce the number of combinations?

Just create subcategories with some variant, for example color. Once one variant is omitted from the combination, there can only be hundreds.

For a larger number of combinations, you need a more powerful server, everything will definitely be slow on some shared web hosting.

Some cache modules will slow down loading rather than speed it up.

[zack24]

Hello and thank you for your response and advice!

We have already opted for a dedicated server with LWS, choosing the VPS PRO M plan. Regarding variant management, we did consider grouping some products into subcategories, but after analysing user experience, we decided to display all variations directly on the product page. This helps reduce the number of clicks and improves the purchasing journey, which aligns with customer feedback, as they clearly prefer this approach.

As for caching, we have noticed extreme slowness right after clearing the cache of our module, and when we disable it completely, the site becomes even slower. We are currently exploring solutions to optimise performance without compromising the user experience.

Thanks again for your input and suggestions! Any further ideas are more than welcome. 😊

[WisQQ]

I believe the issue is not related to fetching data from database but rather processing it into variants. Start by enabling prestashop profiler and check for queries that are called multipletimes. Find the controller/class that is using it and start to optimize it. 
How many variants does your product have? We need exact number to replicate it and see what can be done.

Do you use faceted search on category pages? It can take a toll on initial loading speed as it checks availability of each variant that is assigned to the products.

Do you have enabled OPCache? If yes, check if you have enough memory and keys assigned. 

Another suggestion would be to split the variants load to improve initial page load. For example load similar variants to the default one and defer loading rest with javascript.