when sending svg to files to firefox cppcms is completely sleeping
(<0.1% CPU), but firefox does on my desktop (AMD Athlon(tm) 64 X2 Dual Core Processor 3600+)
about 5fps with 800 lines when using 100% CPU

when less lines get visible, it increases to 6 fps and more


measurements:

time (sec)    frames     frames/second
20            100        5
30            150        5
60            350        5.8
100           620        6.2



TODO investigate:
png refresh rate?
javascript streaming refresh rate?  (http://snipplr.com/view/64803/simple-svg-streaming-client/)