For GPU computing, dedicated memory size will be important or not?

I will by a new laptop and I am considering to use GPU computing with MATLAB. Therefore, I will buy a laptop with Nvidia CUDA GPU. I am asking whether the dedicated graphics card memory size being 2GB or 4GB will differ in terms of the simulation times with MATLAB. My another related question is that while gpu is used for MATLAB simulation, will it only use its dedicated memory or will it also use the system memory. Thanks for your answers in advance.

Answer 1

[Edric Ellis]

The amount of memory available in your GPU should not affect how quickly it performs calculations (all other things being equal), but it will affect the size of problem you can solve. When you convert MATLAB data to be a gpuArray, it must be able to fit in the memory of your GPU - in other words, gpuArray can only access the memory of the GPU device.

[Ali Bulut ÜÇÜNCÜ]

Thnx for your accurate answer.