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PSU Experts


Distinguished Member

It seems I have a very picky motherboard (Abit A-N98HD). I also have a 'specialist' HTPC case (Omaura TF5) which requires low profile PSUs.

I have tried the Seasonic SSU-250 FlexATX psu but this is not enough to power the board.

So, I have found this http://www.powersuppliesonline.co.u...fc-2u-power-supply/400w-2u-pc-psu/default.htm which seems more capable, but is there any way of knowing without actually trying?



Standard Member
It's unlikely to be the motherboard being picky but what you've got plugged into the motherboard. You'll need to find out what the power requirements are for each of the components you use e.g.
Motherboard = 40W
CPU = 100 W
Graphics card = 120 W
each HDD = 20 W
Optical drive = 15 W

These values are probably about 'average' and as you can see a 250W PSU wouldn't cut the mustard.

I'd guess you're safe with the 400W supply, unless you're planning on a monster machine with SLI etc, especially as its an HTPC case!


Established Member
what other components have you got? the 400watt seasonic would be more capable BUT it depends on what other components you are running as drmcw said. if you dont know the wattage of each of your components then just list what you have got and we should be able to work something out


Distinguished Member
There are online calculators that are fairly accurate. If he gives one of them a whirl he'll have a better idea.

As above though, some more system details would help.


Prominent Member
it isnt just how many watts you have it also boils down to how many amps are on the rails and how many your board and card need,what card do you have in it m8


Distinguished Member
No add-in cards, all onboard:

AMD BE-2350 45W TDP
4GB 800MHz RAM (2x 2GB)
Laptop hard drive
Laptop optical drive

The case has a card reader as well.

That's about it I think.


Established Member
age old way of trying to locate the fault... remove as many of the 'additionals' as possible, then one at a time plug in to see when things stop working... either it's bust or it's the overlaod point. It is also worth once 'finding' the problem plug in the next item to see if it's just one piece of kit that overlaods..

...also have these components worked in another system?


Established Member
it isnt just how many watts you have it also boils down to how many amps are on the rails and how many your board and card need,what card do you have in it m8

i think you will find that watts and amps are directly related as we are dealing with set voltages.

and again this applies to the psu output aswell

if the motherboard needs 12amps at 12volts then thats 144watts.
if the psu outputs 12 amps on the 12volt rail then it can provide 144watts. so what it boils down to is watts (and amps as they mean the same thing in this instance)


Established Member
are you using onboard graphics or a seperate card?? i would have thought the 250watt should have been ok but the 400watt will be more than ample from what you have told us provided all your components are not drawing more power than they are ment to due to a fault.

how about fans mate? one on the cpu?? any case fans at all? and lights or anything? (other than the standard hard drive activity and power light)


Distinguished Member
The PSU that I sent back (250W) only gave 8A on the +12v1 rail and 14A on the +12v2 rail. This apparantly is not enough for my board (I have unplugged everything and still wouldn't boot) as a 550W Corsair HX520 powers the entire system just fine.

So i'm just not sure what minimum amperage to get for the +12v rails. The PSU link I posted is 400w but they also do a 460w with higher amperage for an extra tenner, so might just go with that.

Thanks for the replies..


Established Member
if your 250watt has 2 seperate 12v rails which rail where things plugged into?? the 8amp or the 14amp?

i think the 400watt would be fine but if its only an extra tenner then the 460 would give you more headroom and lower temperatures due to less load and probably lower noise due to less heat.

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