The bottleneck is number of points the chart has to calculate and render. For every new incoming data all the points "move" and amount of job needed to be done increases. Second thing is reasonable amount of data points to present. You cant actually fit two points into one pixel. Chart becomes unreadable and loses its meaning. Well you can do wider chart but your display will limit there at some point anyway.
There is no actual number to say to you, it depends on many things, but feeding with 250ms is really fast. Can this kind of fast changing chart do it's main thing - be the statistical reference of your process?
Even if it does, you'll need to reduce maximum number of points the chart needs to be handle at once.
Read this topic also, there is testing flow. You can test your equipment and find the optimal number for your actual setup. https://discourse.nodered.org/t/very-slow-dashboard-dark-at-reload/3456
Copyright OpenJS Foundation and Node-RED contributors. All rights reserved. The OpenJS Foundation has registered trademarks and uses trademarks. For a list of trademarks of the OpenJS Foundation, please see our Trademark Policy and Trademark List. Trademarks and logos not indicated on the list of OpenJS Foundation trademarks are trademarks™ or registered® trademarks of their respective holders. Use of them does not imply any affiliation with or endorsement by them.
The OpenJS Foundation | Terms of Use | Privacy Policy | OpenJS Foundation Bylaws | Trademark Policy | Trademark List | Cookie Policy