Which is faster? Fmt/Scan or Advanced Analysis Library

I want to extract (double) array data from a large array into separate arrays for processing in a loop while still acquiring data off a daq card.

For those operations that are suitably used with Fmt and Scan, would these be better / faster than using the analysis library functions?

For example, which of the following would be the better choice for moving an array subset of 100 elements starting at element 200 ?

count = 100;

i = 2;

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   Subset1D (InBuffer, BufferSize, i*count, count, OutBuffer);

OR

  Fmt(OutBuffer,   "%*f<%*f[i*]", count, count, i*count, InBuffer);

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