Hi @markneutron –
Thanks for your feedback. We wouldn’t generally expect you to see a drop in your site’s speed after installing Jetpack. I am assuming that you are referring to your Google PageSpeed score, correct?
We’d like to investigate this issue if you are willing. Please either create a new support thread or contact us via this contact form:
https://jetpack.com/contact-support/?rel=support&hpi=1
Whether you contact us via the support forums or email, please reference this review and include your site’s URL.