GPU vs. CPU efficiency

I have a GPU on my computer that is "nvidia geforce gtx titan" (which is supposed to be powerful) but I'm not getting any improvements when I run the following code on GPU compared to CPU. It takes ~1.3 sec on both CPU and GPU to run. I was thinking maybe my Matlab does not recognize my GPU so I ran the "gpuDevice" command and it shows that it does recognize it. I was wondering if there is anything that I'm missing?

PS: My CPU is i5 3.2 GHz

clear; clc;
tic
A=gpuArray(rand(1000));
B=eig(A);
t1=toc

clear;
tic
A=rand(1000);
B=eig(A);
t2=toc

Answer 1

[Matt J]

You should time just the eig() calculation. Creation of data and transfering it to the GPU, as in

    A=gpuArray(rand(1000));

is always fraught with overhead. You should also use gputimeit instead of tic/toc. Finally, you should try with different/larger matrix sizes so that you know the GPU is doing a meaningful level of work.