20 watts at idle assignment

[doppis]

Looking for a little guidance for an assignment my teacher gave out. I'm not looking for a direct answer but some kind of input how I can figure this out. I'm pretty sure it has to do with what hardware I'm running but is there anything I need to know about the PSU to figure out the question below???

"In this assignment, you have to select a power supply unit (PSU) for a
desktop computer that consumes approximately 20 watts at idle time and
60 watts at full load. The main criteria for selection is to minimize
wastage of power. Provide a detail rational for your selection."

The question seems like its missing some info...a PSU will run differently on different combinations of hardware correct? Shouldnt he be giving me the hardware that this PSU should be running on?

 

[Brett928S2]

Hi

He already gave you the hint...

Just look for ANY PSU that runs at 20 watts at IDLE...

GOOGLE...

All the best Brett

 

[doppis]

I've been searching all over and I finally starting looking through hardware forums. I'm not seeming to find anything.

Efficiency Up to 86%
Input Voltage AC 115V/240V
Input Frequency Range 50Hz/60Hz
Input Current 10A @ 115VAC / 5A @ 230VAC
Hold-up Time > 16ms
Load Range +3.3V@24A; +5V@20A; +12V1@56A; -12V@0.3A; +5VSB@2.5A

would these stats give me any information on what a PSU would run at idle and load?

 

[ko888]

Take a look at an 80 PLUS Verification and Testing Report and you might get an idea of where the power supply's maximum efficiency occurs.

http://www.plugloadsolutions.com/psu_reports/ANTEC_EA-450%20PLATINUM_ECOS%202882_450W_Report.pdf

 

[hunter315]

The peak power limit actually tells you that you arent looking at an ATX system, you will never get an ATX system running a hard drive, GPU, and CPU thats below 60 W max draw.

This should give you quite a bit of help
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=207

You should be able to limit your hardware options from there

 

[Motopsychojdn]

http://www.scan.co.uk/products/intel-core-i3-2100t-1155-sdy-bridge-25ghz-5gt-s-hd2000-igp-650mhz-3mb-cache-25x-35w-retail
low watt Cpu, there are lower out there though
Mobo with 4pin for the Cpu can't use much power
http://www.scan.co.uk/products/msi-h61i-e35-(b3)-intel-h61-s-1155-ddr3-sata-ii-3gb-s-graphics-on-board-mini-itx
hdd/ram/optical drive won't pull much either, I reckon thats a do-able option
Moto

 

[Gaz1868]

The peak power limit actually tells you that you arent looking at an ATX system, you will never get an ATX system running a hard drive, GPU, and CPU thats below 60 W max draw.

Won't you?
I have
20 watts at idle Desktop; 49/50Watts running a Youtube video + Hyperpi (both at the same time!). Practically silent too!
You just need to be selective about how you build a system

 

[Gaz1868]

Looking for a little guidance for an assignment my teacher gave out. I'm not looking for a direct answer but some kind of input how I can figure this out. I'm pretty sure it has to do with what hardware I'm running but is there anything I need to know about the PSU to figure out the question below???

"In this assignment, you have to select a power supply unit (PSU) for a
desktop computer that consumes approximately 20 watts at idle time and
60 watts at full load. The main criteria for selection is to minimize
wastage of power. Provide a detail rational for your selection."

The question seems like its missing some info...a PSU will run differently on different combinations of hardware correct? Shouldnt he be giving me the hardware that this PSU should be running on?

The power consumption at idle is a red-herring thrown in to confuse you and I dare say, some will look for a power supply capable of 20 watts (like in the first reply you had!) As soon as you drive the PC above 20w that will blow a PSU of a low wattage. You know that the PC will draw 60w under load. Most PSU's run between 80-90% efficiency. An 80w PSU @ 80% efficiency will give you 64w draw = suitable. A 70w power supply with 90% efficiency will give you 63w draw = suitable.