Identifying Pro Mini 5v and 3.3v, Is this correct/safe ?

[Cliff Karlsson]

I have a bunch of Pro minis witch have been mixed. I looked for a way to identify them in a easy way but never found any method that was understandeble to me. But now I just found a super easy way.

Connect 5v to RAW/GND, use a multimeter to check the power of VCC/GND. It shows 3.3v or 4.8-5v.

The post was written by "CrossRoads" on the arduino.cc forum.

Can you measure the VCC pin when power is applied to Raw? If its 3.3V, then you've got a 3.3V/8MHz board.
The chip itself will happily run at 3.3V or 5V.

Is it really this easy?

[fets]

@Cliff-Karlsson yep, that's what I did

[emc2]

If you have good eyes most of the time you can look at the onboard power regulator if it says 5, or 50 (5V) or 33 (3.3V)

[novicit]

On my 5V minis, the 16mhz crystal is much larger (long silver oval component stamped 16.00) than on 3.3v. At least on mine.