Non Maching Results With PSU Calculator

[TheDutyPaid]

So far I have used to online PSU calculators. The one on the ASUS site said minimum of 650W then a different site said 403W quite a difference in power levels.

I was careful to do all the same on both sites.

I there a true trusted PSU calculator site?

[AETAaAS]

I tend to calculate based on known TDPs of the CPU and GPU (by far the most power hungry individual components) then throwing 150W for mobo, drives, etc (in my typical build of 2 RAM sticks, 1 SSD, 2 drives and 2 opticals) then add another 150W for headroom.

I think its a safe calculation, but even with a 1090T and 7870, it comes out to 600W. Nowadays considered the minimum for gaming builds. I think most experienced builders go with what feels right and don't calculate, and then overcompensate since there is little lost by going 10-20% over your calculations.

This calculator has been around for donkey's years and I think it has a good reputation.

Alternatively you could post your build. I'm sure the community would be happy to help.

[Agent]

This calculator has been around for donkey's years and I think it has a good reputation.

No, that has a terrible reputation. Search on here for "PSU Calculator" - the results it gives are not even close to being accurate in most cases.

It doesn't even give you the amps (important) and it calculates capacitor ageing totally wrong. The reasons have been covered many times on here.

[AETAaAS]

No, that has a terrible reputation. Search on here for "PSU Calculator" - the results it gives are not even close to being accurate in most cases.

It doesn't even give you the amps (important) and it calculates capacitor ageing totally wrong. The reasons have been covered many times on here.

Sorry, like I said I almost never use a calculator but I see it linked and referenced on other sites.

[pastymuncher]

A quality 400w psu will be more than enough for your rig if it's the one listed in your profile. I doubt if it would pull 300w on full load.

[D1DM]

You've got to question what methods they use to calculate the power consumption of the system entered. As well as the motivation of the person(s)/organisation(s) providing the calculator. They are very likely to be at least slightly different in each case.

Apart from the fact that multiple power supply manufacturer's often use the eXtreme Outer Vision one, just with different branding, and apparently different implimentations, as someone on another forum once commented to me that if you put the same system config into Thermaltake's calculator you will get a different result compared to the Enermax one, for instance/example.

[TheDutyPaid]

This will be a new build, will be running 17 4770k, 3 HDD, 1 DVD, 5 fans, 1 GTX 560 Ti and 1 cold cathode, so be going with a 750W.

Which is more then I may need but for price there is not much in stepping up to a higher output PSU.

[watercooled]

A ~500W unit would be more than enough for that build, provided you get a decent brand of course. IMO just save your money unless you're seriously considering a heavy overclock and/or multiple GPUs.

For comparison, my 1055t + 5870 system under unrealistic OCCT PSU stress load, draws just under 400W AC, so even less than that on the DC side. That system should draw less, and less again under realistic loads.

[TheDutyPaid]

Thank you all for your help, this has been very helpful, interesting if somewhat still confusing. I took a look at a web site who sell PC's made to your order, chose all the same parts and their PSU started at 500W (of course higher could be added)

I have done 3 more PSU calculators, with results being 403, 600 and 650W

Do they list the power consumption for each part? So I could look up a Motherboard and see it uses X number of watts and add it all together and do the same for the other components.

[watercooled]

PSU calculators tend to over-estimate for a few reasons, one being to compensate for cheaper PSUs which may not meet spec, and for the ones run by the MFRs themselves, because they want to sell you a more expensive one.

Under-estimates may be based on more realistic loads like gaming *or* video encoding for example, not with everything maxed and/or estimate max power draw vs recommended PSU.

You can get an idea how much power your system will used based on specs of individual parts, but use some caution; for example, some parts may draw over their TDP depending on load (and conversely, some may draw less, of course). Even comparing measured power consumption, bear in mind some motherboards may have more/less efficient CPU VRM circuitry than others, and so on.