eAccelerator for WordPress How to make it work properly

I was looking for solutions to speed up my buddypress website because it’s taking ages to load and I’ve randomly found this article which talks about “eAccelerator for WordPress“.

It says to extract the file and upload it to the “wp-content” folder or at least it’s what I understood from it, but when I upload and refresh my website I see no signals of improvement at all. I thought maybe I need to change some settings on “wp-admin” or something but of course I see no tab for it on the WP dashboard because it’s just a single file so I guess that’s it right? upload the file to “wp-content” and it should be working?

I really need to do something about the speed performance. Caching plugins doesn’t seem to do much about it. My hosting server is pretty quick on normal WordPress sites with lightweight themes and stuff, First I thought maybe this could be a theme’s issue for taking so long to load, but I installed a few lightweight buddypress themes and tested its performance and is still taking the same time to load.

Can anybody help me with this?