Speed of read from standard in versus file in Matlab Compiled code

I have the following code to read from standard in, in my compiled Matlab code, which I compiled using mcc -m -T link:exe -N -v -R -nojvm -d build test1.m -o test1

function test1()
    % First, read input stream
    tic;
    stdin=char(0);
    while ~strcmp(stdin,'EOF')
    %while ~isempty(stdin)
        stdin=input(char(0),'s');
    end
    toc;

    % Now, read file
    tic;
    fid=fopen('test1read.txt');
    tline=fgetl(fid);
    while ischar(tline)
        tline=fgetl(fid);
        strcmp(tline,'EOF');
    end
    fclose(fid);
    toc;
end

I executed it as type test1stream.txt | test1.exe (on Windows)

For an order 1.5MB file, I get timing output as

Elapsed time is 1.000616 seconds.
Elapsed time is 0.156772 seconds.

I was a bit surpised to see that reading from input is slower than reading from a file.

For an order 1.5GB file (longer and more lines), I get a timing as

Elapsed time is 78.877386 seconds.
Elapsed time is 95.457972 seconds

My first question would be: why is that? I think one reason is that input() is doing more things than necessary. Is this assumption correct?

My second question is: can I speed up the read from input in a stand-alone tool?

See also: Using standard io stream:stdin and stdout in a matlab exe