Give it a try, maybe dde is fast enough for you. If you are going for highest performance, staying inside Neo will definitely be much faster. I don't use anywhere near 500 symbols. If it will work will depend how complex your calculations are and how often you refresh the quotescreen (on each tick or for example on a 500ms timer). Another factor, if you are using custom indicators/formulas, is in what language you are going to implement them. There are many choices, i.e. Neo's own formula language(easiest for newcomers), scripting languages like vbscript, java-script, or compiled languages like c++ or net. I would suggest asking this on the tickquest-forums, there are a few guys working with that many symbols and can answer these things much better than me.
Im getting euforic! NT quotescreen is running amazingly well on some 450 symbols, a lot of indicators and some calculations. Thank you all very much for the usefull information!!
Did you have to tune NeoTicker's caching settings to get the Quote Window to hum with indicator columns? Also are you still using the NeoTicker DDE link successfully?