The accuracy of the program running by horovod is low

[lljjgg]

When I run the program with "python tf_cnn_benchmarks.py --data_format=NCHW --batch_size=256
--model=resnet50 --optimizer=momentum --variable_update=replicated
--nodistortions --gradient_repacking=8 --num_gpus=8
--num_epochs=90 --weight_decay=1e-4 --data_dir=${DATA_DIR} --use_fp16
--train_dir=${CKPT_DIR}". The final test accuracy is 75.96.%
But I run the program with " horovodrun -np 8 python tf_cnn_benchmarks.py --data_format=NCHW --batch_size=256
--model=resnet50 --optimizer=momentum --variable_update=horovod
--nodistortions --gradient_repacking=8 --num_gpus=8
--num_epochs=90 --weight_decay=1e-4 --data_dir=${DATA_DIR} --use_fp16
--train_dir=${CKPT_DIR}". The final test accuracy is 74%.
Is this a normal result? or This is error that I run the program with horovod.
Looking forward to your reply .Thank you