When you unlock streaming services, performance will indeed be reduced due to the nature of how they're unlocked, which is very different from "normal browsing" on all other sites. In order to unblock streaming services, the traffic is routed through multiple servers, as many as 4 in most cases.
This will be very fast, and you will not see any performance differences. This applies to everything except unlocked services.
You -> Control D proxy server -> Destination site
This will have performance implications, but there is no way around that except in a few narrow edge cases where the last 2 hops are not necessary (which are by far the slowest things in the chain, consuming 90% of the time), as is the case with Netflix unblocking in US, Canada, UK and Japan where we maintain our own residential proxy infrastructure.
You -> Control D proxy server -> Windscribe proxy server -> Residential proxy gateway -> Residential proxy in the country that unlocks the service -> Destination site
TLDR; Control D will have no noticeable speed impact for 99% of your day-to-day browsing. Slowdowns while unlocking geo-restricted services are unavoidable.