How Can HTML, CSS, JavaScript, and PHP Improve Website Speed?

I'd start by measuring where the bottleneck actually is rather than upgrading the server straight away.

For many business websites, optimizing images, reducing unnecessary JavaScript, and avoiding render-blocking CSS can make a noticeable difference to how quickly pages appear and become usable. Caching can also help, especially if PHP is repeatedly generating the same content.

On the backend, I'd check database queries and PHP execution time before assuming the CPU or RAM is insufficient. If the server is regularly running out of memory, CPU usage is consistently high, or storage I/O is a bottleneck, then hardware or a better hosting plan may be necessary.

I'd also distinguish between a slow initial page load and slow interactions after the page has loaded, because they can have different causes.

My approach would be to run a performance test, identify the biggest bottleneck, fix that first, and measure again. That usually gives a better result than trying to optimize every part of the stack at once.