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I'm thinking in substitute my current Core 2 Duo E6400 PC with a Mini-ITX system, described below:

1 x ECS H55-I mini-itx motherboard
1 x Intel Core i3 540
1 x HD 1TB, 7200RPM
2 x 2GB DDR3 memory modules (total 4GB)
No video boards.

The extreme power suply calculator (here: tells me my minimum PSU must be 142Watt, using the 8USB devices. I just don't know if this calculator can be trusted, but it is the first one I found on google.

I do have a mini-itx case, with a real 160Watt power supply, and I got another mini-itx machine with a 120Watt pico-psu unit.

There are 3 questions I'd like to ask you guys:

1) Assuming this 160Watt PSU can be trusted, would my system be in jeopardy with so little margin of use ? (there is only 18Watt "left" to use).

2) Would I be able to add a videocard later (say a radeon HD 5450) on this system, regarding power supply requirements ?

3) Is there any Core i3 or i5 that can be used with a 120Watt Pico-psu unit ?

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up vote 1 down vote accepted

I am running:

Intel D525MW intel Atom dual core 1.8ghz

4GB corsair Ram


Harddrive and using 2 usb ports

on a 80w picopsu

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Im not sure how much that helps, but the intel manual with the MB gave some amp specs on what the power consumption is under full load. – madmaze Dec 1 '10 at 14:29
Could be a clue. I'll look into the ECS manual to see if there is any information about amp specs on full loading. And the big difference between your config and this one, is the Atom versus the Core i3. Atom consumes very few power, about 15Watt only, AFAIK. Core i3 consumes much more on full load, as this says:,review-31890-11.html – Machado Dec 2 '10 at 18:42
No luck from ECS manual... No amps information.... :( – Machado Dec 7 '10 at 1:21
so i went over the tomshardware post again. the i3 systems total power consumption is 80W so 160W would be plenty.. I also assume that means a harddrive is included in that measurement. and even if not they are only ~10-15W – madmaze Dec 7 '10 at 14:19

for that config in an ATX system I would saw, go for corsair CX400..

dont know if it fits in mini itx systems or not though..

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Akash, the problem is that I want to reuse my PSU's and my cases, and I'd like to stick with the mini-itx form factor including for case. I do have a Zalman 460W PSU and an old, but reliable PureFlower 400W PSU that could be used on a ATX form factor, but I'd like to use an i3 or i5 on the mini-itx case. – Machado Dec 2 '10 at 18:49
You should be OK with the 160W. Installing another videocard may not go so well(if you are actually using 8 USB deivces) and the calculator is correct. – Akash Dec 2 '10 at 19:03

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