Mini-ITX PSU question

jm240 · 5 Oct 2011 at 21:11

Hi All,

I notice that mini-ITX cases all seem to come with PSU's but they are very low in terms of watts.

I see a Zotac H55 Socket 1156 motherboard of ITX form factor which reckons it has PCI-Express socket for those who want to throw in a GPU but GPU's need a lot of PSU power so what gives?

I don't see any mini-ITX PSU's for sale either, you seem to have to stick with what comes in the case...

Myocardial Inf · 6 Oct 2011 at 10:15

Depends on what system you run but if you stick with integrated grafics on intel i3 or amd lano then most systems don't actually consume hundreds of watts. In fact an i3 2100 setup can draw as litte as 20-25w idle and up to 55-60w active

Most m-itx cases won't hold the monster cards also, and the lower spec cards don't draw that much power, think the AMD 6770 draws about 110w with Nv cards generally drawing a little more historically (not really up on their lower end products myself).

Also PSU's have generally become much more efficient leading to less loss and therefore lower wattage specifications required to power the same system. Bit of a generallisation in relation to bundled psu's but still somewhat true.

So a 300w psu should be able to power that lot fairly well, with 1 or 2 hard drives at a max of 15w each for 3.5" drives, often replaced these days with SSD's which draw a little less.

Fair enough for an SLI / CrossfireX i7 machine with watercooling etc then you might need a fair amount more juice, but you aren't going to fit that lot in a m-itx case. a lot of people run the i3 systems utilising integrated grafics on 150w pico psu's, which are pretty efficient and have a fair amount of watts to spare.

Hotwired · 6 Oct 2011 at 10:39

ITX cases typically have a 60-150W power supply powered by a laptop type power brick.

A few have a flexATX PSU inside the case which can be up to 300W. Just type in ITX in Google and have a look through the top few links to find some easy examples.

Some ITX cases are deliberately larger to allow a full size ATX power supply, a full size graphics card and accordingly more cooling due to the heat.

Of course you're not bound by any rules, I have a very small ITX case with a 220W power supply and it's got a E8400 and a 5570 graphics card in it.

Idles on 69W and under load it goes up to 138W.

I'm going to attempt an upgrade to a 6750 card later, it still fits within the power limits, the tricky bit is the cooling and the mods required to get it to fit.

mcwildcard · 6 Oct 2011 at 12:27

I'd say if you can track down one of the 45w CPUs then you'll be able to get a decent low powered GPU installed as well.
If so, then you might be able to get away with a 150w PSU.

This list might help you figure it all out:
http://www.geeks3d.com/20090618/graphics-cards-thermal-design-power-tdp-database/

Lunatic Dreyfus · 8 Oct 2011 at 14:58

You can't really have it all with m-ITX. If you want proper GFX you have to start making compromises with the size of your build, or suck it up and go with onboard graphics.

We won't laugh if you do. Promise.

Hotwired · 8 Oct 2011 at 15:08

Lunatic Dreyfus said:
You can't really have it all with m-ITX. If you want proper GFX you have to start making compromises with the size of your build, or suck it up and go with onboard graphics.

What's the standard for a proper GFX?

jm240 · 9 Oct 2011 at 19:40

Hotwired said:
What's the standard for a proper GFX?

Well number one most important characteristic when defining: "Proper GFX" is a standalone Graphics card, nothing on-board and built in!

So if it's bought separate to the motherboard and has around 512mb + memory on the card purely dedicated for graphics processing then you have "proper graphics"

Hotwired · 9 Oct 2011 at 19:48

Well on that front you can easily get the following in low profile and single slot format:

210
220
6570
6450
5570
5550
5450

Without even going outside the mITX motherboard footprint and using a picopsu because they are very low power.

If you're more adventurous there has been a 9800 GT low profile double slot card around for quite a while and now there's a 6750 in low profile double slot which is faster and cooler.

gropingmantis · 9 Oct 2011 at 20:11

What mITX cases are you looking at? The Lian-li Q07, Q08 and Q11 will take full size ATX PSUs and the Silverstone SG07 and SG08 come with 600W PSUs and can fit 140mm ATX PSUs which are readily avaliable up to 700W and Thermaltake even did a 1000W version if you can find one. Anyone saying going ITX means making compromises on GPUs is talking out of their ****. There are SG07 builds on the internet with HD6990 or GTX590.

See here http://hardforum.com/showpost.php?p=1037507945&postcount=624

Bear in mind the SG07 was built around the HD5970 so it will fit any GPU you want.