Internal Server Error after Wordpress Update to 4.3

I am hosting 2 sites on Dreamhost, both seem to have completely slowed down (2-3 mins to load page) and have an Internal Server Error with the text below when trying to edit the page as an admin. Only change appears to be an update of Wordpress to version 4.3. Any help would be greatly appreciated

[i]Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.[/i]

Have you looked in your server error logs?

I haven’t yet, but my site seems to be working as normal again which is very strange, but shall check the logs next time (if) it happens. Thanks for the response