Hi Scotpip,

Yes, you will need multiple Zorro sessions for range bars, which are not that resource hungry, but if you use multiple MT4 sessions for multiple systems it will start slowing down. I'd say 1 MT4, 5-10 Zorro per 1 core per 1GB RAM is ok.

May I ask what kind of range bars are you using, and are you having success adapting them?

edit:typo