Questions about training time consuming

I try to train the scpn model but the training data is too large. I use one GPU. The batch size is 64 and for every batch I need 1.6 seconds to train. But there is 439586 batches. I try to use two GPUs  to train but I fail. Could you tell me how you speed up the training process?  Thank you so much. @miyyer @jwieting 