WP DEFENDER Will either REALLY REALLY slow down or cause Server 500 Error

Earlier this week all of a sudden my site was either super slow or would result in a blank page and a Server 500 Error.

No new plugins were added. Updates were done. Articles were published but that is it.

WP DEFENDER is running on another site of mine without issues and has pretty much the same plugins running.

I have opened up access but currently WP Defender is disabled, however the site is super slow. If I change the plugin folder name on the server, which in essence deletes the plugin, then my site speed is back to normal.

Curious?