You might have noticed the various cache engines available in Dolphin 7 administration. If you look under Tools -> Host Tools -> Cache engines in the current release Dolphin 7.0.4 you will see something like this:
You will see a Yes (available) or No (not available) here on this page or screen.
Whether they are available or not will depend on how your host has setup and configured the server.
With shared hosting what you see here is what you get. You can nicely ask your host if there is any chance they will add any of the cache engines that say No (not available), but don't count on them doing so.
If you have vps or dedicated server with root access you can install the others if you want to go through the time and work of doing so. Just make sure you know the particular cache engine is compatible and will work with your current server setup.
I spent several days testing File Cache, EAccelerator, and Memcache with a default Dolphin 7.0.4 install.
The testing was done on a vps server with suphp with fgi, Mod Php/DSO/Apache Handler, and Fast Cgi.
Like Boonex has suggested in:
Hosting Server Setup Recommendations for Optimal Dolphin 7 Performance Mod PHP/DSO and Fast Cgi are fast.
Suphp with fgi is a bit slower, but has a slightly better security when compared to Mod Php.
When testing compatible cache engines with each setup I notice very little difference in speed or page load times.
The only time I notice a difference at all is if I compare Mod PHP/DSO or Fast Cgi to the Suphp with fgi setup. It doesn't seem to matter which cache engine I use with each setup, the differences are so slight that they are almost unnoticeable. So it tends to be more about the way php is compiled and configured that will increase performance more than which cache engine is used.
Overall Suphp is much slower as expected partly because it has to load and reload php so often. Because of this I don't know that Suphp is such a good choice for a VPS where cpu and memory power is often small and limited.
I do like Suphp on a fast and speedy server that is not overloaded with a bunch of other accounts.
Generally if you get VPS hosting what they set you up with is a fairly simple Mod Php/DSO/Apache Hanlder configuration. I am just not a fan of this type of setup.
Again if you have shared hosting you will be limited to whatever your host has installed and available.
For VPS or Dedicated with root access you have more freedom and control, for a price, and depending on your knowledge of course.
File Cache is pretty basic and simple. EAccelerator and Memcache will require a bit more work to set up.
I almost like Memcache better. It seems to be a little more consistent than EAccelerator with the configurations I have been testing anyway.
If I had shared hosting I would prefer Suphp with a speedy server and limited accounts.
Fast Cgi and Suphp are a toss up if the server is fast. I would take Fast Cgi over Suphp when the server or host is a bit slower.
I am not a fan of Mod Php at all anymore.
A lot of shared hosting companies use Suphp I would guess because of easy setup and they can track an individual account resource usage much easier. But, if a host is using this setup and puts too many accounts on the server it can get slow in a hurry.
If I had my own VPS or Dedicated server I would use Suphp if I had a fairly powerful plan. Otherwise, I would use Fast Cgi with Memcache or EAccelerator.
All Dolphin folders/directories can be 755 even the upload folders/directories. Ffmpeg.exe should be set to 755
You can install Dolphin with this setup in just a few minutes because all files and folders remained owned by your account. Which means you do not need to set a bunch of file permissions during install. The only exception will be ffmpeg.exe which you will need to set to 755. This alone saves you a ton of time.
See this Dolphin Tutorial for more info:
How to install Dolphin with Suphp
You will need to set upload folders/directories to 777 as indicated by the installer. Ffmpeg.exe will also need to be set to 777. This can take a lot of time.
Any file generated or created through your web site will become owned by the server and you will not be able to edit, change, or delete it by means of ftp client. This creates problems with things like Orca Language file/directory related. You can sometimes reset them back to owned by your account by using your hosts control panel. This is time consuming though. Mod Php will outperform Suphp in terms of speed.
See this Dolphin Tutorial for more info:
Reset or Restore Files Owned 99 By The Server
Can be a bit more confusing. Usually you do need to set upload folders/directories to 777. However, ffmpeg.exe is often be set to 755 with this setup.
Files created or generated by your site might be (99'd) by the server depending on the setup. You may or may not be able to edit, delete, and change them with ftp. Most Fast Cgi setups I am able to delete them. So this is still much easier to work with than mod php. Fast Cgi will almost always outperform Suphp by a lot.
Make sure you do some research and know what you are doing before jumping into one configuration or another first.