So I've only ever built one computer I don't have much experience and I was hoping I could pick some brains.

I would like something quiet, and cheap to leave on 24/7 (I often use the computer remotely both as a cpu and as file/webhosting). The goal would be to be able to power it off a 150W picoPSU. Truthfully I'm too intimidated to try for any less. The current parts plan is:

processing: core 2 quad 65w, I'm willing to consider other intel chips, however I do a lot of cpu bound computations, and I need to be able to use the intel compilers so I'm pretty attached to intel as a brand. I plan on undervolting to the maximum degree possible without underclocking.
storage: ssd - almost no power dissipation, also blazing fast
motherboard: I have read onboard video is more efficient than a card, so I guess that's a start, and I know I want an intel chip, so that narrows it down a bit more, what about "ASUS P5Q-EM LGA 775 Intel G45 HDMI Micro ATX", I don't even know where to start in estimating the power of a board, I'm looking for something that has pretty extensive undervolting options, both for the cpu and the ram (if one can realy undervolt ram)
memory: 2 x 2g @ approx 20w/stick? 40W, I found some rated at 1.8-1.9 volts so hopefully they would be lower than this?

So I'm looking at 65w proc + 40w mem + ?board(guess 40?) or 120w. I'd like to have a cd/dvd burner drive. I was thinking an external one, especially usb powered, that way I can just plug it in when I need it? I think this would use less power than having an internal? I even found one which is powered on just one usb, which I believe guarantees it pulls less than 2.5 watts.

Finally since I won't have the psu on the back of the case how can one cover up that opening? And where does one usually route the pico psu into the case? I was thinking getting some acrylic and making another window? Drilling acrylic is probably within my skills (especially since it can be super thin).

newegg list: 10786745

What you need is very similar to what I'm building see http://www.silentpcreview.com/forums/viewtopic.php?t=55084
I use a Q8400S 65W quad core and it will undervolt easy with a good motherboard the problem will be the north bridge heat.
The RAM power consumption will be at least 10x less then you expected probably less than 4W so that is not a problem.
Yes the internal DVD uses some power an external one is limited to USB max output that is 2.5 Watt so much better.
I have the same problem with the opening left by the old power supply but it dose not bother me at the moment I guess acrylic will work.

I guess I should share that the numbers I estimated are from newegg's wattage calculator which comes up when you look at power supplies there.

On the machine I previously built I got an 80+ silver power supply, but it provides much more power than I'm using. I wonder if I might have gotten better efficiency by using a smaller psu at only the bronze or certified level.

I promise you RAM will not take 40W I have 2x2GB RAM and the entire system is only 30W at idle the ram is probably about 2 max 4 W in total.
The CPU and north bride are the main consumers.
If you list the spec I can calculate for you.
The power supply is efficient in the range of 20 to 80% of the spec power but a 80+ power supply even if bigger will be more efficient than a 65+ efficiency power supply.

Roughly what I'm thinking. I'm not sure which of the intel or nvidia integrated graphics would consume less energy.

wait for it...

http://secure.newegg.com/WishList/PublicWishDetail.aspx?WishListNumber=10786745

I totally trust you on the ram, I just wanted you to know that I did do some homework and wasn't just making stuff up.

I believe you but I'm electrical engineer and I know the difference between 2W and 20W If RAM module will take 20W it will need a big heatsink and fan.
About intel vs nvidia if you are referring to G41 vs 9400 then G41 will require less power but it will also be less powerful it depend on your needs.

Have a look at the power usage from this SPCR Intel 9550S review.

A heavily undervolted 9550 + discrete 9400GT + Velociraptor 300Gb + 4Gb RAM is just under 120W at full CPU load.

A lower stock clocked CPU with similar levels of undervolting in the Q8xxx or Q9xxx range with only integrated graphics and an SSD should fit in under 120W as well.

I assume your CPU bound computation work benefits from a quad core CPU, which is why you want to go down the quad core route.

Have a look at SPCR's motherboard reviews to see which boards undervolt well. I think the Asus board you mentioned (or one very similar to it) has been reviewed.

The problem with a picoPSU is finding a brick to match the wattage rating of your system.

I knew that when undervolted a normal 45nm 95W TDP quad core will be the same as a "S" 65W TDP version. So it dose not make sense to pay 100$ premium for the S "65W" version of quad core.
I got mine very cheap from eBay because it was an engineering sample it was cheaper than the normal quad core If I remember correctly I payed 150$ including shipping for the Q8400S.
The big problem when you want to use a PicoPSU is not the CPU especially if you undervolt but the 5V power consumption of the motherboard.
For example my motherboard based on G31 will use minimum 4.8A to about 6A when you load the integrated video card and this is probably the lowest power draw for a modern motherboard on the other hand the 3.3V uses max 2A.
I will be curios if someone tested a G41 or G45 motherboard power consumption on the 5V line or a nvidia 9300 or 9400 integrated video.

And that 6W @ 5V you quote is the maximum continuous output that the pico psu is rated for @5V.

If you use a graphics card instead of onboard video does it pull power from the 5V or the 12V?

I have not tested tested currents with a dedicated video card but it will still take a minimum of 4.8A and I don't know exactly how much a dedicate video card will use the 5V but they take a minimum of 20W so it is not a very good idea if you want a green computer. The integrated video card is still the best solution.
Te big video card use a dedicated 12V connector but I guess they still use some 5V and 3.3V

I'm confused, if a motherboard with integrated graphics alone will possibly draw more than the maximum sustained 5V output of the psu (6A) doesn't that mean that I need to use a different psu? Which defeats the purpose here.

In my previous post W should have been A, the motherboard is pulling about 6A at 5V or 30W total?

i power my desktop from a 150w psu.

specs:

cpu: intel e5200 OC to 4ghz
RAM: 4gb ddr 800 ram
Storage; 30gb ocz vertex.
GPU: GeForce 7300 GS

total power consumption when folding is 130W (18w of that goes to powering the Water pump) measured at the plug with a killawatt

The motherboard include LAN sound HDD controllers memory and more and the CPU uses only the 12V line for power so if it dose not exceed the 6A the picoPSU will be fine My board based on G31 will take max 6A so the PicoPSU 150W will be fine but If I want to add some HDD or DVD drive then will not be enough The power supply I use will give 7A on 5V line and I have no problem will even give more than 7A if needed for some minutes.
PicoPSU is intended for small computers based mostly on VIA or Atom boards but they will also work with basic computers I have no experience with new chipsets as G4x from intel or the new Nvidia 9300 or 9400. The old Nvidia 7xxx had low power requirement.
for intel chipset you can see a comparison of max TDP see this http://www.silentpcreview.com/forums/viewtopic.php?t=35078

I was about to create a new thread but used the search instead and decided to post my question to this thread. Hopefully it is ok.

I am planning to buy a PC case which comes with a 60W power supply. I don't know yet the current values of the DC board for the different voltage levels. I think the AC/DC brick is a 60W / 12V.

I was wondering what might be the power requirement difference between a setup with one DVB tuner product in PCI bus and a setup with two DVB tuner products using PCI bus.

Do you guys have any estimates on this. Basically I am hoping to find out that how much a PCI bus DVB tuner product requires power?

Is it so that mostly the PCI bus product loads the 5V and 3,3V lines (or only one of these?) and no 12V at all?

I think the Atom330 based setup would pretty much be on the limits of the PSU section and I would like to try to be sure that the line is not crossed.

I used to have a DVB card when I was living in Europe and I do not know the exact power consumption but it was getting quite hot so I will say that it will be a minimum of 3W and a max of 6W and is true that they use the 5V line and some times the 3.3V but not the 12V line.
From my knowledge there is only a PCI on Atom boards so you can only use one and you will be fine I think with the 60W power supply.
If you need a second DVB you can use an USB one or even two and in this case if the 5V line will be to stressed you ca use a powered hub to solve the problem and a 2.5" HDD will be a good choice.
One more thing to consider is using an ION based Atom board the Intel chipset will not be able to play 1080p i guess. My old setup was a Athlon XP 1800+ with a GF 5200 and a Skystar 2 DVB-S on PCI and was able to play the 720p channels but the 1080p was just a slide show.