Unfortunately I miss your point. The ideea was to have the same operations in the timed loops. I was not trying to also have the data avaialble somewhere. Maybe the operations should look like:

for (int i = 0; i < dimension; i++)
{
float temp = matrix1[i] + matrix2[i];
}
and
for (int k = 0; k < repetitions; k++)
{
ParallelArrays.Add(pmatrix1, pmatrix2);
}

I was pointing out just raw power not access latencies.

DisposableFloatParallelArray pmatrix1 = new DisposableFloatParallelArray(matrix1);
DisposableFloatParallelArray pmatrix2 = new DisposableFloatParallelArray(matrix2);
DisposableFloatParallelArray pmatrix3 = new DisposableFloatParallelArray(matrix3);
//….
for loop

and, after the calculation with the normal forLoop u have the result in the maxtrix3-Array

in the Gpu-calculation u DONT have the managed float array after calculation, so u cant use it to display it or so.

when u want to show, that one algorithm is faster than another, both have to do the same.
so put the array deklaration oft the ParralelArrays into the loop, and write the result back in a managed float Array.
and u ll see, that its much slower than the normal calculation

(sry, my english ist worse )

Try matrix multiplication instead, (since it is computationaly harsher).
I have a GeForce Go 7400 and my computation limit is bound to 4096 elements.
Which is very low. =(