Predictably, Sony's PlayStation Now service requires a fairly good internet connection. According to their SCE social media manager Sid Shuman, that equates to a 5MB net connection.
That's for a 'good' PS Now experience, apparently.
“And as with all bandwidth-intensive streaming content, a player’s experience with PS Now will depend on the overall quality of the broadband internet connection,” he said
“The PS Now team is currently estimating that a 5 mbps connection will provide a good experience for most games, and they’ll be gathering user feedback during the closed beta before announcing more details.”
Shuman added, “At this early stage of PS Now’s development, pixel counters and graphics aficionados might spot some minor concessions in the visual department, such as compression artefacts, consistent with high-quality internet video or gameplay streamed via PS Vita Remote Play.”