how many watts do I need?

socialsupernova · Post by **socialsupernova** » Tue May 27, 2008 10:47 am

I'm building a new/home theater computer and am trying to make it as quiet and energy efficient as possible. My goal is to use this computer for web browsing, 720p playback, music, light photo editing/web design and playing some old emulators. I am planning on putting it in my bedroom so I want it to be as close to silent as possible.

I was thinking an ASUS P5E-VM HDMI but I heard that it had a high idle power consumption, however I wouldn't need a video card and I don't have time to wait for the g45's. I was going to match it up with a E8400 and scyth ninja, 2 gigs of cheap g.skill ram, a quiet asus optical drive and a 7200 rpm laptop drive. I was going to throw all this is in a mini p180.

My only question is what should I do for a power supply? I was thinking about this one but is it overkill?
http://www.newegg.com/Product/Product.a ... 6817151035

Do I really need 330 watts? I was thinking about fanless but would that be a bad idea with a fanless HSF.

Licaon · Post by **Licaon** » Tue May 27, 2008 1:22 pm

http://extreme.outervision.com/psucalculatorlite.jsp ?

angelkiller · Post by **angelkiller** » Tue May 27, 2008 2:02 pm

Technically speaking, 330W is overkill for that system. But with today's marketing: "bigger is better", PSUs don't come smaller than 300W these days.

By getting a smaller power supply, you increase the efficiency of the computer. Small load on a large PSU is inefficient. PSUs are most efficient between 20% and 80% of max capacity. So ideally, you want your computer's power draw to be within that range.

If you do want a smaller PSU, have a look at a Pico-PSU which is a DC-DC converter. A power brick converts AC to DC but at smaller wattages. (Normally 60W or 120W) Then the Pico-PSU converts the DC voltage to voltages the computer uses. This process is extremely efficient and great for low powered computers.

Hope this helps.

socialsupernova · Post by **socialsupernova** » Tue May 27, 2008 5:46 pm

According to the psu calculator I need 182 watts, is the pico going to work for me?

tehcrazybob · Post by **tehcrazybob** » Tue May 27, 2008 6:55 pm

One of the larger Picos could work, but it's very difficult to find the AC-DC power brick to support a 200 watt Pico. However, I've found that particular PSU calculator to always predict an unreasonably high level of consumption. Take a look at this one, which I have found to be much more accurate.

thejamppa · Post by **thejamppa** » Wed May 28, 2008 2:55 am

Its damn shame that Spakles 250W 80+ PSU is so hard to find... That would have been very good choice. Another good is Fortron Green 300W.

Post by **NeilBlanchard** » Wed May 28, 2008 9:05 am

Hello,

thejamppa wrote:Another good [one] is Fortron Green 300W.

I concur -- the Fortron Source Green 300watt PSU is inexpensive ($45.28 shipped at NewEgg), >80% efficient, and very quiet. I am building a system (E8400, 2GB Corsair, 320GB WD SE16, Asus P5K, X800XL, Xigmatek HDT-1283, Asus DVD-RW) as I type, and it is very quiet.

amyhughes · Post by **amyhughes** » Wed May 28, 2008 10:26 am

thejamppa wrote:Its damn shame that Spakles 250W 80+ PSU is so hard to find... That would have been very good choice. Another good is Fortron Green 300W.

The OP is in the US and so has several choices. Last I checked buy.com had the Sparkle 250W, and had the lowest price. I bought mine after reading the spcr review and I'm happy with it.

maalitehdas · Post by **maalitehdas** » Wed May 28, 2008 2:59 pm

Older seasonic 350W or newer seasonic 380W would probably be worth consideration in your system? If your need is around 180W, the idle and load consumption's probably fits into the 20-80% cap mentioned in post above

potsy · Post by **potsy** » Wed May 28, 2008 3:36 pm

182w sounds a bit high to me, especially if you're using the onboard graphics. I'm using an mCubed 200w fanless which has a rated peak of 280w.

My system in my sig below has an idle power draw is 49-59w, at load up to 74w. I can't get it up to 100w.

If you want to see the mCubed have a look at mine here (except this was before the mobo/cpu update):potsy's puter

sonics · Post by **sonics** » Wed May 28, 2008 9:41 pm

I am wondering if you can use a 20 pin picoPSU in a 24 pin motherboard?

potsy · Post by **potsy** » Wed May 28, 2008 9:55 pm

You can. My mCubed is a 20 pin and the mobo is a 24. I just bought one of these: ebaylink Seems to work fine.

If you search there is some discussion here about it, like this: "You can get a 20-24 pin converter cable, but most of the time it's not necessary, the 20-pin male connector fits into the 24-pin mobo socket and normally works, IIRC the extra 4 pins supply power to the PCI-E bus, so if you have a powerful GFX card this may not work." on this thread: linktothread

Plissken · Post by **Plissken** » Wed May 28, 2008 10:39 pm

NeilBlanchard wrote:I concur -- the Fortron Source Green 300watt PSU is inexpensive ($45.28 shipped at NewEgg), >80% efficient, and very quiet.

Neil is right, this is an amazing PSU. I've built 2 systems with them and they are everything everyone says: quiet, efficient, solid, and inexpensive.