Can conditional write into scatter stream speedup kernel?

Discussion created by Raistmer on Aug 31, 2009
Latest reply on Sep 1, 2009 by gaurav.garg
Or better to eliminate if() at all ?

I need to store value in GPU memory only if some condition (pretty rare one) is true.
In other cases (most probably) computed value in register can be discarded w/o storing it in scatter stream.
Will if() condition speedup kernel (cause memory operation required only in small part of all threads) or it will just slowdown kernel cause memory write always will be no matter what condition value is?

And how to speedup such writes (rare writes in big scatter array) ?

if(was_signal>0){ dest[threadID][0]=o11; }