I'm also having an issue with high CPU usage.
I have narrowed it down to wpForo because I deactivate the other plugins, but it doesn't change the CPU usage. All I have to do is Deactivate and Re-Activate wpForo and the CPU usage drops significantly, from close to 100% to less than 10%.
But it usually only lasts for a few hours. Then I have to Deactivate and Re-Activate wpForo again which solves the problem again for a few hours.
I've been doing this for about a week now and it's very consistent behavior. Deactivating and Re-Activating wpForo solves the problem every time.
Sometimes my Deactivate and Re-Activate wpForo solves the problem for around 6 hours like in this example (I took this screenshot after Deactivating and Re-Activating wpForo which is why the usage has already dropped):
Other times it only solves the problem for about an hour or so like you can see here on the far left (I took this screenshot after Deactivating and Re-Activating wpForo which is why the usage has already dropped):
It took a lot of back-and-forth troubleshooting with my hosting provider (A2 Hosting). Originally we were down the path that I posted about here (click here). But they were very helpful and persistent and eventually narrowed it down to the Deactivate and Re-Activate wpForo solution.
In the logs we can see that the reason for the high CPU usage is the high number of processes which you can see in the second screenshots above. The processes are repeatedly accessing wpForo pages.
It makes me wonder if the caching feature is out-of-control. I'm going to try disabling the cache here in a moment to see if that solves the problem.
I bet this is a hosting problem and not wpforo. Or some other plugin.
50 processes !!!!!
To me it seems like something is stuck and doesn't release the process/cpu etc or something.
