I have been trying to program Atmega328p au- custom board using both arduino uno as ISP programmer and USBasp programmer. When I program Arduino UNO GENUINE Board the code runs fine but on my custom board the same code runs 10 times slower. Even in simple LED blink code the delay() works slower on my custom board than Arduino UNO Board. Did not make any changes to IDE default settings for either.
Custom board details:
Controller: Atmega328p_au (smd TQFP package)
10K pullup for reset pin,
16Mhz crystal with 22pF caps
0.1uF accross all VCC / GND
Custom board powered using VCC from USBasp or Arduino UNO as ISP. But same result when powered with external 5V power
Any help will be appreciated