what does setting torch.backends.cudnn.deterministic to True or False do?

On my GTX1080, when I run waveglow, the speed is dramatically slower if I turn torch.backends.cudnn.deterministic = False compared to True. However, the speed is not changed on some GPUs whether I turn this on or off – ex. GTX 1050Ti’s speed of running waveglow as not impacted.
So what does torch.backends.cudnn.deterministic do? and why does it impact speed on some GPUs and not others?

What does torch.backends.cudnn.benchmark do? and what impact on speed does it have?