Hello,
Glad to hear that you like Wordfence!
There are a few things that you can do.
Live Traffic:
You may consider disabling Live Traffic to reduce the load on your web server. Simply go to the Live Traffic page and disable this feature.
If you want to use the Live Traffic feature then you can reduce resource usage by extending the Update interval to ease the problem when viewing the Live Traffic page. This setting is near the bottom of the Options page. By changing this setting which controls how often the live data is refreshed, from the default of 2 seconds to something like 10 or 15 seconds, you dramatically reduce the amount of processing power that viewing Live Traffic page (or the Scan page) will consume.
Scanning:
If you are a free Wordfence customer, then scans occur once a day and we choose the time that the scan occurs during a 24 hour period. You can disable the Automatic scheduled scans option and choose to do a manual scan at a time of your choosing when you expect traffic to the site to be low. This option is near the top of the Options page.
You can also enable the setting Use low resource scanning. Low-resource scanning spreads out the scan’s work over a longer period of time, to help decrease the chance of high resource usage in a short period of time. This setting is in the Scans to include section on the Options page.
I would also review the documentation on the various scan settings that you may want to disable to reduce the time it takes to do certain scans:
https://docs.wordfence.com/en/Wordfence_options#Scans_to_Include
