cannot reproduce the results of moco-v2

Hi, is there anyone have successfully reproduced moco-v2?
I have tested several times, but still cannot achieve the same results metioned in README.md. Actually, I can only get 45% in top-1 accuracy in linear classification using my unsupervised training 200 epochs model, and get 64% in top-1 accuracy using the pre-trained model given by the author. The top-1 accuracy in linear classification task metioned by the author is 67.5±0.1.
My environments are as follows:
Python: 3.8.3
GCC: 7.3.0
GPU: Nvidia A40, training using 8 gpus
CUDA: 11.0
Pytorch: 1.7.0
Is there anyone can give me some advice? Thanks.