Your concern shouldn't be of a concern to you...
The thing is Nest too had enough back fill on daily if you applied the date range in the plus historical chart....
In anyway catering to your question, I applied a 4000 bar history with a 5 minutes interval and the chart's first candle was dated 18th June 2014.... That is for the 5 minutes interval.
I guess backfill on the hourly and daily should be enough to make you a millionaire....
....
And about the accuracy, I do not compare two charts from different sources or compare Zerodha's with NSE either.. There are technical aspects that get involved like latency of the connection and the server's location which cause the delay or any sort of discrepancy relatively. What we should understand is we trade with whats in front of our eyes, the rates that pop on our terminal.
For example, if we place an order with price 100 and trigger also 100 and when the candle on the chart reaches 100, if the order gets executed, that is enough because if the feeds aren't accurate, I am sure the order wont be executed because our limit order never gets its price.
And Zerodha's feeds have been good enough. I guess the feeds are from Omnesys and Omnesys is the one that is used by most other brokers, so chance of any discrepancy is minimum to zero....
And by the way, the platform has been smooth on my other desktop... Was working with commodity charts, did not trade on it but kept loading multiple charts to test it....No problem at all which points to it being a little resource demanding (considering its performance on my other comp) but what the hell, when it makes money, why do we worry about money....
Zerodha....Kudos...