In theory if your gpu has enough compute, then running all 3 will be the same as running 1 yes.
It is really unlikely that your gpu will have enough compute to do that.
Also if you start measuring time by looking how long it took to run a python code line, keep it mind that the api is asynchronous which means it is not because the line executed that the code actually ran on the gpu. If you want to wait for all operations to finish on the gpu, use torch.cuda.synchronize().