PicoPSUs

Cheetah Designs · 2 Apr 2012 at 23:18

I am looking at using one of these small PSUs in a IB build.

The CPU I was looking at was the equivalent of the SB-2500k which has a TDP of 77W. I will be using the IGP so won't have a graphics card.

The only other things that I think will require power will be the SSD, motherboard and CPU fan. There is no optical drive.

Will a 120W one of these small PSUs be enough to power this system or do I need to look at the 160W version? Last time I built a machine was ages ago and you had to check the 12V rails (or something to that accord)...is that something I still need to check?

Sasahara · 3 Apr 2012 at 00:31

Even the 160 W version won't be up to running a SB-2500k.

It's max load is only 8 A on the +12 V, so 96 W.
(Peak 15 A - not to exceed 60 sec)

TDP of 77W is just for the CPU, you still have the mobo and any other component to run. You'd certainly not need a K, CPU overclocking would be instant PSU overload.

These are really only suitable for very low power 1-2 core CPUs. Maybe a AMD Llano A4-3300 based system.

Edit, I think even this might be a push. You probably need to run a CPU with a 35-45 W TDP, to be safe.

Sasahara · 3 Apr 2012 at 00:40

For an i5 system you will probably have to use an i5-2500T.
45 W i5.

http://ark.intel.com/products/52212/Intel-Core-i5-2500T-Processor-(6M-Cache-up-to-3_30-GHz)

Cheetah Designs · 3 Apr 2012 at 09:41

Hmm the logic doesn't make sense.

So for the CPU it takes all its power from the 12V rail, does any other component do that?

So assume I get the 160W PSU and it has over 90% efficientcy, meaning it has 87W on the 12V rail so 10W is left, are you telling me that 10w isn't enough to power a SSD, a fan, a motherboard and two memory dimms?

The Halk · 3 Apr 2012 at 10:15

The PSU can supply 160W in total. However it can only do 8A sustained on the 12V line, which is where the CPU requires most of the power from. That's 96W, the CPU requires 77W which means you have 19W for other components. Power supplied doesn't need to worry about efficiency. The motherboard I would expect on it's own to consume more than that. The fan, and memory don't consume much, perhaps 10W, but a chipset is likely to do it.

So sticking strictly to the spec of the PicoPSU then you're probably a little bit outside. However I think you'd be fine.

You could go for one that would be more suited - PW-200-M 200W, which supplies a fair bit more, enough in my opinion not to worry about things, on the 12V line.

You do know that a PicoPSU requires an external power brick? Just in case that ruins the aesthetics of your build.

Cheetah Designs · 3 Apr 2012 at 11:28

The Halk said:
You do know that a PicoPSU requires an external power brick? Just in case that ruins the aesthetics of your build.

Yeah I am aware of that. It was going to be one of my next questions. I obviously need a brick that supplies 160W or 200W or whatever. Does it matter if its 12V or 20V or something else.....does it have to be 12V?

chippy08 · 3 Apr 2012 at 11:35

Cheetah Designs said:
Yeah I am aware of that. It was going to be one of my next questions. I obviously need a brick that supplies 160W or 200W or whatever. Does it matter if its 12V or 20V or something else.....does it have to be 12V?

Depends on the pico some are WI which means you can use between lets say 12-20v brick.