I dont use wpdiscuss, so I am not sure what tables should be in which database, but I think if you do that, itll fix the problem. 

I had the same issue with wpforo, and as soon as the tables where in the right places the site was 4 x faster. 

I am using your comment plugin and purchased an addons bundle.
But too much slowed my website down.

https://www.modartpc.com/

All addons are installed individually. You can see the problem in the page speed test.
My eliminate render-blocking resources values are too high. The caching plugin does not benefit your application.
For this reason, I request a refund.
I will use the free version.
Please get back to me immediately.
Have a good weekend.

https://developers.google.com/speed/pagespeed/insights/?hl=tr-TR&url=https%3A%2F%2Fwww.modartpc.com%2F&tab=desktop