Quick answer: Measure first, then apply the big four: full-page caching (LiteSpeed Cache, FastCGI cache or WP Super Cache), PHP 8.3 with OPcache, a Redis object cache, and image optimization (WebP + lazy loading). On a VPS these are all under your control and typically cut load times by 2–5×.
Overview
WordPress performance is a stack of layers: the closer to the visitor a request is answered, the faster the site. Page cache serves whole pages without PHP; object cache saves repeated database work for the requests that must run PHP; OPcache removes script compilation; and lean media keeps transfer small. Work top-down and re-measure after each layer.
Before you start
- A baseline: run PageSpeed Insights / WebPageTest and note TTFB and LCP.
- Know your web server — the best page-cache choice differs for Nginx vs OpenLiteSpeed.
- A backup before stack changes.
Step-by-step guide
- Page cache: OpenLiteSpeed → LiteSpeed Cache plugin (already integrated); Nginx → enable FastCGI caching in the server block or use a caching plugin. Verify with response headers (
x-litespeed-cache: hit/ your cache’s header) and exclude cart/checkout/account pages on WooCommerce (details). - PHP: run PHP 8.3 with OPcache on (default) — and size FPM correctly (PHP tuning).
- Object cache: add Redis (guide) — the biggest win for wp-admin, WooCommerce and logged-in users.
- Media: serve WebP (Performance Lab plugin or your image plugin), keep lazy loading on, and let the browser cache static files for 30 days (expires headers).
- Trim the app: deactivate unused plugins, prefer a lean theme, and find slow queries with Query Monitor before blaming the server.
- Re-measure. If TTFB on cache hits is still slow, the server itself is undersized — consider NVMe VPS or Power VPS plans.
Common issues
- Two page caches at once: plugin + server cache fighting causes stale pages — run exactly one page cache.
- Cache hit ratio near zero: cookies or session plugins marking every visitor dynamic — check the cache-status header on incognito visits.
- Fast front end, slow admin: page caches don’t help logged-in users — that’s the object cache’s job (slow admin guide).
When to contact support
If the site stays slow with confirmed cache hits and healthy CPU/RAM graphs, or you want advice sizing an upgrade to NVMe/Power VPS, open a ticket with your measurements.
Frequently asked questions
What single change speeds up WordPress the most?
Full-page caching — a cached page is served without running PHP or touching the database, routinely cutting time-to-first-byte from hundreds of milliseconds to under fifty.
Do I need a CDN if my VPS is close to my visitors?
Less than you would think: for a single-region audience a nearby VPS with good caching often matches CDN latency. A CDN pays off for global audiences and heavy media.
Why is my site fast for visitors but slow when logged in?
Page caches skip logged-in users, so every admin request runs full PHP and SQL. A Redis object cache and PHP/database tuning are what speed up wp-admin and WooCommerce.
Related articles
- How to configure Redis object cache
- How to optimize PHP for WordPress
- How to optimize MariaDB for WordPress
- WordPress performance checklist
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