Do SSL Cert signed by Intermediary CAs cause additional delays
compared to SSL certs signed by root CAs?
Whether the certificate is signed directly by a root CA or is a 'chained SSL certificate' has no impact on the request time of the SSL connection.
However, changing the encryption level of the certificate will impact the time it takes for you to process SSL transactions. If you went from a 40-bit certificate to 128-bit, for example, it will take almost 3x as long for the necessary calculations to take place.
If your application is making an "excessive amount of SSL calls" then you can look into some hardware based SSL cards that are specifically designed to increase the performance of SSL calculations.
