PSU Calculator

[Fraz]

Have you got a linky for the energy usage monitor please?

This is where I got mine from:

http://www.reuk.co.uk/Kill-a-Watt.htm

Although that Ebay link may potentially end up cheaper for exactly the same thing.

I ordered it on Monday, got it yesterday. Was ~£24 with P&P, which is £4 less than if you went to Maplins, plus it saves you the walk

Also, if you want it delivered to an alternative address that isn't your card billing address, just send him an email after you've made the payment.

It's pretty nifty... tells you kWh, PFC, Watts, Volts, Amps, Hz, and VA. Well worth the money - especially as it'll save you from ever buying a massively over-specified PSU ever again...

[iranu]

I've used that calculator before. It seems pretty good. I'm supposedly at 376W peak. If I drop down to 1 HD and lob a 8800gtx in I come out at 378W peak, which is what I'm planning unless I can hold out for new cards in November.

Wow, a high performance AMD dual core uses >150W?

I am going to have to think twice about going 430W now...
(big price difference between a Seasonic 430W and a Seasonic 500W PSU).

You might want to look at a 520W Corsair HX only £12 more than the 430W Seasonic

[mnemonik23]

Hahahaha - it's officially bollocks. Look at <----- My System. What do you reckon the maximum power draw of that is, with all four cores going, and the graphics card fully loaded?!

285 Watts at the wall socket!

So, My PSU is ~80% efficient, so the actual components are only using ~230 Watts.

So what on earth is the point of a 700W+ PSU?! Clearly you can easily power a twin 8800 Ultra gaming rig with a 500W psu... 600 is already more than enough!

Fraz,

Before you start blaming the calculator please double check what you select.
I ran you system trough the calculator, added DVD RW, a few USB devices, Sound card, a few fans, etc. and got 399W at 100% absolute load and 339W with 85% load (which I recommend).

I bet you selected Dual or Quad Processor as System Type. You should select a Single processor since your Q6600 is a single processor. This is a common mistake people do while dealing with multi core CPUs.

Also, it's almost impossible to 100% load ALL of the components at the same time and that's why you get lower results from the wall outlet. Calculator assumes that all components are stressed out and that's why I recommend to use 85% load.

So, 339W-285W=54W difference, which is not bad

[Fraz]

Fraz,

Before you start blaming the calculator please double check what you select.
I ran you system trough the calculator, added DVD RW, a few USB devices, Sound card, a few fans, etc. and got 399W at 100% absolute load and 339W with 85% load (which I recommend).

I bet you selected Dual or Quad Processor as System Type. You should select a Single processor since your Q6600 is a single processor. This is a common mistake people do while dealing with multi core CPUs.

Also, it's almost impossible to 100% load ALL of the components at the same time and that's why you get lower results from the wall outlet. Calculator assumes that all components are stressed out and that's why I recommend to use 85% load.

So, 339W-285W=54W difference, which is not bad

Indeed you are correct - I ran it again with the correct system type and get 381 Watts, which is rather more realistic.

Apologies

[mnemonik23]

Indeed you are correct - I ran it again with the correct system type and get 381 Watts, which is rather more realistic.

Apologies

No problem at all!

[mildlyAmused]

I noticed this was giving me a really high wattage for the system I'm building. Then I noticed I'd mistaken Quad Processor for Quad Core. Dropped the wattage from 985W to 653W. It even says right under the drop down... user error, doh!

[TooNice]

You might want to look at a 520W Corsair HX only £12 more than the 430W Seasonic

Haha, thanks, but I don't think the Corsair was around around that time [I've since built my machine around an 'overkill' 600W Seasonic]. Even the modular Seasonic wasn't out around then.

I might grab one of that meter usage monitor too though.

[Clunk]

Mnemonik23...I have a mains tester thing coming tomorrow, would the results from that reflect what the PSU calculator tells me, or have I done something drastically wrong?



Thanks

[mnemonik23]

Mnemonik23...I have a mains tester thing coming tomorrow, would the results from that reflect what the PSU calculator tells me, or have I done something drastically wrong?

Thanks

First of all I must say it's one sweet setup you have!

Recommendation: use 85&#37; or 90% for CPU Utilization and the same for System Load.
So far I haven't seen any real life test that shows CPU utilization of 100% TDP. EDIT: even if you overclock it, use the above %. Calculator automatically adjusts OC.

I think the question is: will you be able to stress out all of the above components at least 85% while looking at tester? Probably not, so the results from the tester will be lower.

I see you selected additional PCI-e 4x card. Please note, that for these additional PCI-e cards I use maximum wattage that each of PCI-e slots can produce. In case of 4x it's 25W. In your case it could be less...

[Clunk]

Thanks

The 4x PCI-E card is a RAID card with 6 SATA drives attatched.

Using the previous settings but with 85% utilisation, it comes out dead on 900w or 768w with 85% system load.

Is the 85% system load thing just to offset the components that may not be used normally?

It is the CPU and GPU that I am most curious about. How do you get the wattage figures for the overclocked CPU? I'm not doubting them, just curious

[mnemonik23]

Is the 85% system load thing just to offset the components that may not be used normally?

Yes and no Mostly yes. As I mentioned before (maybe not on this forum), components are divided by groups. Say, you have different CD ROM drive models from different manufacturers and the Wattage can be anywhere between 12W and 20W (old models) for example. So I use average wattage per group, in this case it will be approximately 17W. But for most critical components I use the high end of the range (HDD, RAM, etc.), which makes calculator to overestimate power in some cases but from the other side it covers you 100% and you won't be sorry if something burns because of your less powerful PSU...

It is the CPU and GPU that I am most curious about. How do you get the wattage figures for the overclocked CPU? I'm not doubting them, just curious

CPU OC formula is not a secret

Pnew = Pspec * (Fnew/Fspec)*(Vnew/Vspec)^2

P = Power in watts
F = Frequency in MHz
V = Voltage
new = new overclocked values
spec = published specifications (TDP)

Hope this helps!

[Supershanks]

was just trying to remember that myself. It's pretty widely used & accepted. Used it ourselves in this project on AMD64 Probably the most correct PSU calculator you can use for MSI K8N Nvidia Neo's many moons ago

So i guess it's stood the test of time

[Clunk]

Thanks for that.

What I was meaning was, do you ever test the figures against real, overclocked/overvolted CPUs to see if the figures match?

[mnemonik23]

Thanks for that.

What I was meaning was, do you ever test the figures against real, overclocked/overvolted CPUs to see if the figures match?

It's kind of impossible for us to test 750+ CPUs...
But we did test a few. We also work closely with some of the online review sites and gather information from everywhere possible. I was surprised when in some cases the figures were close to +/-3W !!! In some cases + 18W (with power hungry CPUs like 90W+). I must say it's pretty darn close.

[Clunk]

Excellent, I will post my results if the tester thing arrives tomorrow

[Clunk]

Right the tester thing has arrived.

On bootup just over 400w.

Idle is just under 380w. (no power saving enabled).

Under load with prime95 beta on all 4 cores, kaspersky AV scanning, is just under 500w (489-498w).

I started the oZone3d OpenGL Fur benchmark as well, and the power rose to a maximum of 580w.

At the moment, the CPU only has 1.45v and is clocked at 3.2Ghz.

I will try the 1.65v/3.6Ghz settings later.

Everything else is on full, such as the fans, pumps etc, and everything that I was able to stress was being stressed.

Not entirely sure what to make of that yet