That's surprising. Is it the example here (http://code.shutterstock.com/rickshaw/examples/extensions.ht...) that is slow? How is it slow (when you click on controls to customize the view, drag a slider, mouse over plots)? When it's slow for you is there something else on your computer chewing up a bunch of CPU?
A lot of the hard work is being done by d3, which is pretty well optimized for the tasks its doing. I'd be surprised, even on a 4-5 year old commodity desktop, to see laggy or jumpy behavior with fewer than a million or so plot points.
If you're using an SVG renderer, you'll get significant slowdown with many fewer than 10^6 points. It's not D3's fault. SVG backends build a complete DOM for the representation (so using JS with it is trivially simple), but browsers do not appear optimized for million-node trees. In my experience, you'll see noticeable slowdowns starting with ~30k points or so.
If you're using canvas, that's an altogether different story. (But then you're stuck doing object location yourself, for example)
A lot of the hard work is being done by d3, which is pretty well optimized for the tasks its doing. I'd be surprised, even on a 4-5 year old commodity desktop, to see laggy or jumpy behavior with fewer than a million or so plot points.