I've read that Litespeed is a lot faster than Apache. I use mostly WordPress and Joomla sites and am looking for a new server. Will I see a significant increase in speed of WordPress being on a LiteSpeed server?
As of 2021, some of the "improvements" that Litespeed has developed vs. Apache are more theoretical than practical, such as HTTP/3 support (UDP-only) which is not even widely supported:
The more "core" features of Litespeed are their PHP handler LSAPI (LSPHP) and server-level cache which they call LSCACHE (not to be confused with the WordPress plugin they also released separately). The benefit here is that the same vendor is coding all these things, which means they should work smoothly together and can follow a more accelerated development timeline, etc.
One of the biggest reasons that people assume Litespeed is "better" than Apache is because they don't realize Apache already supports multiple caching methods, but that is simply not advertised well by most web hosting companies who prefer making money from selling WordPress cache plugins, etc, or by calling their caching feature something ridiculous like "ABC HOSTING SUPER CACHE".
The other major reason is because Litespeed has invested considerable effort into "confusing" WordPress users especially by publishing dishonest benchmarks showing that Litespeed performance being much faster than both Apache and even Nginx -- dishonest because, they did things like disabling FastCGI Cache on the Nginx server to ensure it performed slower, among who knows what else.
At the end of the day, Litespeed is a private company trying to "replace" open source Apache with their own proprietary software and aggressive marketing, which is why experienced users are skeptical. If you want to know more about Apache features in particular it might take you a little bit more digging since Litespeed works with several different bloggers (and web hosts) to promote their own "performance", but the truth is out there for users who are interested.
TLDR as I posted on SO, Litespeed is not "faster" than Apache or Nginx when it comes to e.g. loading speed, but they can claim the ability to scale insane traffic levels (e.g. shared cPanel hosting) better than Apache, if that's what they want to claim... of course, this doesn't matter to Nginx users, anyways, since high-traffic sites on Nginx are not using bloated control panel software... and standalone Apache users shouldn't care either, since they are not running a massive overloaded shared hosting server. If you ARE planning to run a shared hosting company and dumping all your customers on the same instance, you might consider using Litespeed.
No you will not see a significant increase in speed just by being on a litespeed server. They claim it serves PHP 50% faster (than mod_php) but they haven't updated their SAPI in over a year. PHP-FPM will blow it out of the water any day.
Stick with open source and if you want a web server that really is faster take a look Nginx
There are a lot of LiteSpeed haters out there, and I can only speak from experience. I've found that LiteSpeed handles memory much better than Apache. I switched to LiteSpeed on a VPS that hosts about 20 WordPress websites and the reduction in server wait and page loading time was significant. Switching to LiteSpeed was also very simple --- it integrates well with WHM/cPanel, and in my case my hosting company took care of installing it. I'd highly recommend you give it a try.
I use an Apache with PHP-FPM process manager for serving PHP, and Nginx for serving the static content, with a Varnish cache in front of the entire thing.
You see a lot of hosting companies offer PHP-FPM + Nginx like this nowadays. I don't have any benchmarks on how this compares with LiteSpeed, but I have used both setups, and they both work great. The important thing is I would make sure that you're not using the default mod_apache process manager if your using Apache. Other than that, it shouldn't really matter if you choose Apache or LiteSpeed.
I trialed (the free version of) lightspeed in 2021 to tried squeeze the last drop of speed out of webhosting, after reading all the promises of faster speeds with newer protocols etc.
I was disappointed that, for the identical website, the lightspeed result on a new server with no load was indistinguishable from my standard Apache setup (which has customer load on it on a similar specced server). It seems to me that in practice the results are not there, although if you are starting off, Lightspeed has a nice GUI and makes some things easier.
I discontinued my test and continued with Apache (because it hooks into my systems). I do note that the sites I host are not high volume, so YMMV.
Sorry if I go a little bit off topic here, but I just wanted to comment on this subject although maybe most of these things you will already know.
When you want to speed up a WordPress site there are a few steps you can take that will make a major difference.
Another thing that will make a major difference will be a CDN. You can use CDN's such as Amazon S3 and CloudFlare to distribute your static files to servers all across the world and serve them to users closest to those servers. This will increase the speed of your website dramatically.
If that is still not enough than you can resort to changing to a different web server. I can not tell you a lot about LiteSpeed, but I do have some experience with Nginx and I think they will perform almost the same.
From my experience Nginx is a little faster than Apache, I had the exact same WordPress site on two servers, and Nginx did a lot better than Apache. I read that it had something to do with the way Nginx spawns the processes, but that is a topic for ServerFault.
To conclude, changing your web server can make a difference, but be sure to have your site optimized before switching.
For WordPress speed, the difference is minor, wherever you use LiteSpeed or nginx servers, that's not the main factor.
For hosting companies I think they prefer LiteSpeed, because it reduces costs, support, adds more security and performance.
But for the end user (even more on shared hosting) the speed difference won't be even measurable.
I think one of the main advantages of LiteSpeed over apache or nginx servers is that you can do (easily) server-based caching with a free plugin, that is practically premium in terms of functionality + no ads or premium version (LiteSpeec cache). The plugin really works like a charm, making it easier for everyone to speed up their website.