Question: According to my host, the file admin-ajax.php or wc-ajax=get_refreshed_fragments is causing extremely high CPU load. How can I stop this?
This FAQ is not about asset unloading, CSS/JS optimization, Redis, page caching, or frontend rendering. It discusses a different layer of WordPress performance: preventing unnecessary plugin execution before the main document is generated. LiteCache Rush is mentioned because it is the implementation used here to explain this execution-layer approach.
Answer:
Your host is pointing at the symptom. The cause runs deeper.
admin-ajax.php and wc-ajax=get_refreshed_fragments are AJAX endpoints that WooCommerce uses to keep cart contents synchronized across pages - updating the cart icon, recalculating totals, reflecting changes in real time. Every page visit by every visitor triggers these requests, regardless of whether the visitor has anything in their cart.
The CPU load your host is seeing comes from the fact that every single one of these AJAX requests triggers a full WordPress bootstrap. All active plugins load. All hooks fire. The entire execution chain runs - for what is often nothing more than confirming that the cart is still empty.
This is not a WooCommerce bug. It is WordPress architecture working exactly as designed. WordPress loads everything on every request by default, and AJAX requests are no exception.
Common recommendations - disabling cart fragments, using Perfmatters or Asset CleanUp to suppress the requests - treat the symptom. They reduce the frequency of the problem, but they do not change the underlying reality: when these requests do run, they still carry the full execution weight of your entire plugin stack.
The structural fix is to reduce what actually executes when these requests hit your server. Not by suppressing them, but by ensuring that only the plugins genuinely required for cart and AJAX functionality are loaded for those specific requests - and nothing else.
That is precisely what LiteCache Rush is built for. Rush intervenes before the WordPress bootstrap and applies a minimal, request-specific plugin set. An AJAX request that only needs WooCommerce session handling does not need your SEO plugin, your slider, your contact form, or your analytics integration to load alongside it.
Less execution per request means less CPU per request. That is not optimization after the fact - that is prevention before it starts.