Why the rknn inference time in toybrick is better than firefly with the same rk3

I run the same benchmark program on a toybrick 3399pro and a firefly aio3399proc board and the inference time in toybrick is much better!?Toybrick: inference time 0.035, fps:28.73
Firefly: inference time 0.049, fps:20.56

firefly log

toybrick log