If your first-party extra domains are advertised in your SSL cert, then Chrome at least will use the same connection for those assets too.<p>See this: <a href="https:&#x2F;&#x2F;blog.cloudflare.com&#x2F;using-cloudflare-to-mix-domain-sharding-and-spdy&#x2F;" rel="nofollow">https:&#x2F;&#x2F;blog.cloudflare.com&#x2F;using-cloudflare-to-mix-domain-s...</a>