Try to change your Linear(1000, 1000) to this model from the tutorials:
class ToyModel(nn.Module):
    def __init__(self):
        super(ToyModel, self).__init__()
        self.net1 = nn.Linear(10, 10)
        self.relu = nn.ReLU()
        self.net2 = nn.Linear(10, 5)

    def forward(self, x):
        return self.net2(self.relu(self.net1(x)))


Logs will tell
...
cuda:1 2048
cuda:1 3072
...

Looks like it took reserves blocks of 1024