What OS are you on?
I just tried this small snippet on Linux (CentOS7) and on OSX:
import torch

a = torch.ones(800*3*480*640)
print(a.eq(0).sum())
torch.save(a, 'a.pth')
b = torch.load('a.pth')

print(b.eq(0).sum())

On Linux it works fine, on OSX i get an error, which i am investigating:
0
Traceback (most recent call last):
  File "a.py", line 5, in <module>
    torch.save(a, 'a.pth')
  File "/Users/soumith/code/pytorch/torch/serialization.py", line 120, in save
    return _save(obj, f, pickle_module, pickle_protocol)
  File "/Users/soumith/code/pytorch/torch/serialization.py", line 192, in _save
    serialized_storages[key]._write_file(f)
RuntimeError: Unknown error: -1