CrossAbove vs. >

[Argo1]

Is there any difference between:

if (CrossAbove(RSI(RSIPeriod, RSISmooth), 20, 1))
  EnterLong();

and:

if(RSI(RSIPeriod, RSISmooth)[1] > 20)
  EnterLong();

or is it the same?

[NinjaTrader_Austin]

There is a very big difference.

The first snippet you posted will only be true the bar after the cross above occurs.

The second snippet will be true for every bar the RSI is greater than 20.