Power Adaptor relationship to Power Supply

[eatumup]

Im sure the answer to this questions is out there but unfortunately I don't really know how to phrase the question.

I have an old dual core ITX computer that is running off a standard power supply that i stuffed into an xbox360. I want to replace the power supply with a pico power supply for more room and less heat, but I am unsure about the power adapter I need to buy for it.

I am unsure when it comes to the wattage, So when it comes to something like this 200w Pico power supply; what is the wattage I need from my power adapter?

At first I thought 200W needs 200W. My confusion comes from kits like this one where a 60W power adapter is supplied with a 90W power supply.

How does the wattage between the two parts relate?

 

[turkey3_scratch]

What is your computer? You need an actual power supply for a computer, those Pico things aren't for normal computers, they are for small electronics. Not sure if Rasberry Pi's use them or not (happy pi day BTW).

What is your computer case? An ITX computer will typically use a normal ATX power supply, if not SFX. You can't fit a Pico PSU into those things. I mean, I guess you technically could use a Pico PSU, but it requires an external PSU anyway that supplies the 12V DC.

 

[eatumup]

What is your computer? You need an actual power supply for a computer, those Pico things aren't for normal computers, they are for small electronics. Not sure if Rasberry Pi's use them or not (happy pi day BTW).

What is your computer case? An ITX computer will typically use a normal ATX power supply, if not SFX. You can't fit a Pico PSU into those things. I mean, I guess you technically could use a Pico PSU, but it requires an external PSU anyway that supplies the 12V DC.

The computer is stripped down as it can be. The case is an Xbox 360. it is a mini itx 775 (core2duo 1.6) using on board graphics and 2 gigs of ram. The computer is basically used as a media server.

Did this once before with a friend maybe 15 years ago back when ITX was just on the European market. He used it as his car computer for a while. I remember using a pico power supply for it back then.

Anyhow, finding the needed wattage of the power supply isn't where im stuck. Its making sure that the external 12v psu is enough for the internal psu. Pico seems to be the way to go since the power brick can be scaled down to a laptop power brick and be safe outside the case, instead of the mini atx power supply i have stuffed in there right now.

Here's some pics of the 360 rebuilding back in 2011.