Adding gpus but without improvement of training speed

[blablabLACK]

Hi, I am confused about the multi-GPU training speed.

Firstly, I trained the CIFAR10 dataset on my 2080 Max-Q (8G) GPU with default hyperparameters, and it took about 40 hours. Then I transferred the code to another computer equipped with 2 RTX-2080 Ti (12G) GPUs to train with the same parameters, but it still took 40 hours.

Why does this happen? Could someone give me some tips to improve the speed?

Thanks!