Isn't 1 minute the same like 60 seconds?

[gofortips]

I noticed that running a backtest using a 1 minute graph doesn't give the same results than a 60 seconds graph (being the rest of the parameters the same). I'm not talking about a little difference, it's really different!
What's the reason of this and Which is the right one to use for backtesting?

[NinjaTrader_Bertrand]

gofortips, you would need to keep in mind both are build from different source data :

1 minute is build using minute data
60 secs is build using tick data

So given the source data is different you can see varying results when comparing backtest results on those series.