Running atmega 328p on 3.3 v

Hi guys,

I trying to run an standalone Atmega328p with 3.3v and external clock (8Mhz).

i followed the CrossRoads's way that is burnbootload "ProMini, 3.3 V 8 MHZ" board first.

i use an USBISP interface to do it and i feed it with 3.3v.

Unfortunatly after burnbootload, i upload "blink" sketch to test it and i haven't any sign of good work except in 5v.

What am i doing wrong ?