Power requirements for this build enough?

Question

I am currently in the process of building a series of desktop base units to act as a cluster (running Linux). It will be running 24/7 mostly so i need something that lasts. Here are the specs:

• CPU: Quad core AMD fx4100.
• RAM: 16GB (4GB per core)
• GPU: not required (i.e. any card that can output to HDMI - 50 W power usage maybe?)
• HDD: 500 GB
• Cooling:3x200mm fans.

Since I will need a certain number of the above, it would be great if somebody can advise me on the specs. I have used AMD for a while; will Intel be better for this?

My budget is about 300-400£ per node (i don't need a case); I'd like to know if this can be obtained for cheaper.

I haven't decided on the number of nodes, but I do not want to be limited by the PSU. I am considering the Corsair series (Corsair CMPSU-800GUK Gaming Series GS800 High Performance 800W Power Supply): is this a good choice?

How else can I bring the cost of this system down? The nodes will be connected via Ethernet.

Answer 1

While i can't advise with any certainty on machine specs for the use you intend, i can however recommend a great little tool that i use when assessing power requirements for a system build:

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

Just plug your hardware in and it will give you a relatively accurate ESTIMATE of the power requirement needed to run said spec.

Hope that helps to answer at least one part of your question!

Answer 2

While my comments are additional to those by Dean and others, I'd like to bring up a point or two which is important enough to merit it an answer.

First of all, I agree with Lil' Smokey; 800W is probably much more than you need. My rig is about the same as yours above, WITH a medium/high performance GPU (Radeon HD 6670), and I run 200W when under full load. I have a 470W PSU and have NO problems at all.

So for Wattage, that PSU calculator is your best bet. If I had to make an educated guess, I'd say the 500W range should be enough for you, given my experience above.

The important part: Your PSU should be 80 Plus Certified! This makes things run cooler (less heat produced by the PSU), and could lower your electricity bill (given a high power factor). The higher the certification (Bronze through Titanium) the better.

The 80 Plus article above also makes a good point about choosing a PSU of the "appropriate" Wattage for your setup.

Take the following example (roughly from the Wikipedia article above):

Say you have a 500W PSU. 80 Plus certification guarantees you that the PSU is at least 80% efficient at 20% or higher load.

20% * 500W = 100W. So your 500W PSU is only guaranteed 80% efficiency at 100+ Watts.

If your PC idles around 60-70W (very likely for most setups, including yours), it doesn't mean you're getting that 80% efficiency. The higher Wattage your PSU is, the larger this range between idle and 20% becomes, decreasing idle power efficiency.

Moral of the story: It's not always best to say "Screw it, I'll get a 1200W PSU! Go big or go home!!1!11" Choose wisely, and choose as low as you think you can get away with.

Good luck!