Topic: Which PSU for this rig? (Read 2942 times)

1kW PSU is a good choice for 4x5870 mining rig. 800W pulling from PSU, but for 24/7 duty you need some reserve. Due to capacitor aging you need 20% reserve for 1+year life span with 24/7 utilization.
http://extreme.outervision.com/psucalculatorlite.jsp

I agree with that.

Look at this article and the chart:
http://www.legitreviews.com/article/1080/13/

In "CrossFire", the HD 5870 system approaches 600W under full load. Keep in mind that the less GPU bottlenecked that the system is, the harder the CPU will work, thus increasing power consumption by the CPU. In simple terms, not all of the additional consumed power is going to the graphics card.

...
The difference in powerconsumption between "Crossfire" and a "Solo" graphiccard is about 250W.

So, 2 more 5870s in a rig at full load and overclocked you have to add about extra 500W to the 600W (Crossfire) shown in the article above.  => 1100W => Therefore buy a 1200W PSU to be on the really safe side.

I'm not overestimating, I'm making a recommendation. A little headroom gives extra protection from the downtime caused by having to do an RMA. And a good PSU can last a long time, so getting one that's has a couple hundred Watts extra might save you from buying another one if power requirements are different next year.

You don't need 2 GB.

1GB will do just fine for a dedicated rig.

Naturally, the 70A is meant as total output of the 12V rail. You can't count on all those amps being available to the video cards; but in a dedicated mining rig, the cpu, motherboard and fans shouldn't use more than maybe 50W from the 12V rail. Even far less if you do your power saving homework .

You are correct this is not how PSU efficiency is measured, however you are incorrect about getting 70A out of a 12V rail on a 850W PSU....unless of course you don't have a motherboard attached to that PSU. If you want 70A out of a 12V rail and intend to use a motherboard and other peripherals such as a CPU/RAM/drive/etc you will need ~1KW depending on other components used.

And if you want to have a real beast in your rig then use this one:

http://www.amazon.com/Antec-HCP-1200-Energy-Certified-Supply/dp/B004DBA2O6/ref=sr_1_1?ie=UTF8&qid=1307840391&sr=8-1

Enough connectors for your graphic cards.

Have fun!^^

cul8'er.

Here is my recommended PSU for you:

http://www.amazon.com/Antec-Power-Quattro-1200-TPQ/dp/B002EP30GK/ref=sr_1_1?ie=UTF8&qid=1307839451&sr=8-1

Read reviews. http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=166

Site is packed with in-depth reviews of PSUs.

4x5870 would be no problem, 5x5870 will be cutting it a bit close. Don't get me wrong, it's a very good PSU (it supplies 80A on a single 12V rail,  basically perfect for a mining rig), it's just that 5 5870s will push even that close to the limit. But if you optimize your power consumption (underclock your cpu, underclock the memory on all video cards, don't overvolt the GPUs), it should just about handle it. Still, for five 5870s, you're probably better off playing it safe and getting a 1.2kW unit.


How is estimating about 200W per 5870 in a 4-way rig 'overestimating' needed power? There's more to power supplies than just the number printed on the box. What really matters is the 12V rail, which will supply close to 100% of the power the video cards will draw. A 1kW PSU with a 36A 12V rail is just plain crap and it will actually be dangerous to use it in a 3x or 4x 5870 rig. There's a realistic danger of something in the PSU blowing up, melting, etc., possibly causing damage to attached components or even starting a fire.
That said, a good 850W PSU (70A @ single 12V rail) can handle 4 5870s, if you optimize power consumption and don't overdo it with GPU overclocking. A 1kW unit is still a safer bet though.

That's not how PSU efficiency is measured. The rated Wattage is what the PSU can output, not what it will draw from the socket. So, an 850W PSU will actually give you ~800-850W to play with, depending on the rail configuration. Again, the important one is the 12V rail, which in a typical quality 850W unit will deliver 70A or thereabout, so ~840W.

I measured at wall (via Kill-A-Watt) a cheap non-IGP MB loaded with a Sempron 140, 2GB DDR3, 2.5" SATA and a simple PCI video card at a little under 70W with CPU running at full load, no load at about 52W.

An 85% efficient 850W would give ~722W to play with, minus 70W for system leaves ~652W for GPUs. ~652W/4 = 163W per GPU available.

I would be safe and go for a 1KW PSU if at all possible. 163W per 5870 GPU is cutting it mighty close IMO unless you do some aggressive underclocking/undervolting.

As usual everyone vastly over estimates needed power. Running a 4x5870 rig and a Kill-a-watt monitor I measured my rig to pull about 900Watts from the wall on a gold standard PSU, which means about 785Watts to the system.

So any quality 800 - 850Watt PSU will do you fine, just make sure you get something with either a single rail, or rails that can handle the amperage you draw for the GPUs.

Miners will be much louder than power supplies.  These size fans are virtually silent compared to the 58xx's.

Wow... okay. Thanks for the warning.

What do you think of this one?

http://www.amazon.co.uk/CoolerMaster-Silent-Pro-M1000-internal/dp/B002SP2FVM/

Its 100W and (I hope) silent.

Could this support five 5870s?

Thanks again for your help.

Those are some really shi**y specs. All the power on the 3.3V and 5V rails is basically wasted because most power-hungry components in today's systems (cpu and video cards) get most of their power of the 12V rail. Manufacturers of quality power supplies have adjusted their rail distribution and power ratings accordingly, so an Antec, Corsair, Enermax, etc. PSU will be able to deliver 85%+ of it's rated power on the 12V rail (there are more good PSU manufacturers, I just can't be bothered to list them all ).

Shi**y manufacturers like the one that made this PSU try to scam people with inflated Wattage and cheap components; kinda like with PC speakers . This piece of sh*t would deserve maybe a 500W rating and even then I wouldn't have confidence it could reliably power a 2x5870 rig. 3x5870 is already way out of it's specs.

As for what PSU to actually get - just get any >=1kW model with ~80A or more on the 12V rail. If you had more experience with tweaking your system's power usage you could get away with a good 850W unit.

No, don't get that PSU. Not unless you want to upload "House on fire, EPIC PC failure!!!" to Youtube. It has seriously weird specs.

I'd say get something that's in the 1000-1200W range, just to have a little margin. I like Corsair personally due to good experiences, but stuff like Antec, Seasonic have good rep, and there are others like be quiet!, Fractal Design, Cooler Master and more that are good if you pick the right one. Expect to spend around the equivalent of €200 and up to get something you can trust with all that hardware.

Hi guys...

I've never built a PC before and I need some advice. I decided to build a rig and ordered the following parts:

Board: MSI 890FXA-GD70
GPU: 4 * Radeon 5870
Ram: 2gb
CPU: Sempron 140

And I intend to run it off a USB boot of Ubuntu.

What I need to know is:

1) What kind of PSU would suit this rig? I want to get one that is quiet (that is my priority) but also one that could support another 5870 if I decide to fill in the final slot on the motherboard. My second priority is that it needs to be cheap. And thirdly, it needs to be available via Amazon UK or Ebay. Would something like this 900W PSU be suitable?

http://cgi.ebay.co.uk/Storm-900W-Quiet-Silent-PC-Power-Supply-PSU-Black-/300537779936

2) Would I need any risers or extra converters for the PCI slots, or extra power leads from the PSU to the cards? I really don't know what I'm doing here and how to fit all these parts together. I don't know if I need any extra parts not listed?

So here I am as a newbie that would be grateful for any advice. Thanks for your help guys.