Optimizing ViT-B-16 Transformer Training: How to Accelerate Training Time

Hi, I am attempting to fine-tune the ViT-B-16 transformer on the ImageNet and SUN397 datasets. However, it currently requires at least 2 days to run for 15 epochs, and I also need to fine-tune the hyperparameters. I am utilizing 4 GPUs with 40 GB of memory and a batch size of 512. Is there any potential way to accelerate the training time or identify hyperparameters that won't take as much time?

computervision datasets gpus imagenet least memory training transformer vit