Color flash on boot

[Doryfied]

Hello reader !.

My PC has a weird problem. The problem has existed for a while now but I never could figure out what it actually is!

Sometimes when I start my pc, there are colors flashing on the screen, White, green, red and blue. I chalked it up to the GPU not being able to post properly. Sometimes it happens when I have some external device plugged in. I power off and start again and the pc boots and posts properly without any problem!! 

I have an Intel i5 -4670

16GB Corsair vengeance RAM

Zotac GTX 1050 mini 

 

It isn't a huge problem, but I'm just curious to know what it is. 

 

Thanks!