what you can do if your SharePoint is sometimes very slow.

E.g.: on the first start of a Site
Sometimes during the day a search query will take about a minute until you get results.....

Just look on that article: http://support.microsoft.com/kb/2625048

it will improve "feeled" performance (site response times) massive, if you're going to implement both solutions.

Disabling CRL Check is just necessary if the SP Server does not have internet connectivity, that means proxy settings must be configured for the server itself

http://technet.microsoft.com/de-de/library/bb430772(v=exchg.141).aspx, and your proxy must allow traffic from the server of course.