Programming use Bus Pirate as ISP Upload Speed is too slow

Hi,

Recently I have started to use Bus Pirate as ISP to program my ATmega328P, the size of the sketch is only 67%, and it takes me 5 minutes to upload the sketch into the chip.

I wonder if there is a way to increase the speed as when I use the Arduino IDE to program the Pro Mini it only takes few seconds with the same sketch size.