Estimated Wattage

[Emceeschw3pp3]

How accurate is the PCpartsPicker Estimated Wattage feature?
example: http://pcpartpicker.com/p/p34pRB this set up includes dual 970's and an i5-4690k all at under 500W. Should the estimated wattage be trusted when picking a PSU or does one always have to do outside research to tell if they will have enough power?

[79wjd]

For dual 970s I'd get at least a 650w psu, although less would be perfectly fine, it's just better to not run a psu at 100% load. 

 

An EVGA G2 750w psu would be my recommendation 

[Emceeschw3pp3]

For dual 970s I'd get at least a 650w psu, although less would be perfectly fine, it's just better to not run a psu at 100% load. 

 

An EVGA G2 750w psu would be my recommendation 

I thought the fact that the selected PSU was platinum rated meant that it can run at 90% load with no issues or is that just marketing crap because, the amount of times people have recommended selecting a lower rated PSU (in terms of precious metals) is staggering.

[79wjd]

I thought the fact that the selected PSU was platinum rated meant that it can run at 90% load with no issues or is that just marketing crap because, the amount of times people have recommended selecting a lower rated PSU (in terms of precious metals) is staggering.

Technically any decent psu (this includes 80+ bronze too) can run at 100% load no problem. But it's still not ideal to run a psu at 100% load due to efficiency and putting more strain on the hardware. Peak efficiency is usually around 50-60% load (on most psus). 

[WoodenMarker]

I thought the fact that the selected PSU was platinum rated meant that it can run at 90% load with no issues or is that just marketing crap because, the amount of times people have recommended selecting a lower rated PSU (in terms of precious metals) is staggering.

No, that's not how efficiency works. A 500w psu should be able to output up to 500w regardless of efficiency. A less efficient psu just pulls more power to do it . 

 

PcPP is pretty decent with its rough wattage calculations. http://www.guru3d.com/articles-pages/geforce-gtx-970-sli-review,4.html

What PcPP lists isn't a psu size recommendation though but a rough guideline to power draw.

 

A decent 650w would be good: http://pcpartpicker.com/part/evga-power-supply-110b20750vr

[Mujteba]

No, that's not how efficiency works. A 500w psu should be able to output up to 500w regardless of efficiency. A less efficient psu just pulls more power to do it . 

 

PcPP is pretty decent with its rough wattage calculations. http://www.guru3d.com/articles-pages/geforce-gtx-970-sli-review,4.html

What PcPP lists isn't a psu size recommendation though but a rough guideline to power draw.

 

A decent 650w would be good: http://pcpartpicker.com/part/evga-power-supply-110b20750vr

Same reason the AX1500i can work off a single 120V wall socket as opposed to two.

[MegaDave91]

If you want the most efficiency then you will want somewhere in the neighborhood of 750w. If you're not concerned with efficiency then something like 620w will suffice.

[WoodenMarker]

If you want the most efficiency then you will want somewhere in the neighborhood of 750w. If you're not concerned with efficiency then something like 620w will suffice.

Actually a 620w would be more efficient. Due to a system usually not being oc'ed to the wall and at 100% load 24/7, an as small as possible psu is generally more efficient than one that's larger than necessary. 

[Emceeschw3pp3]

Peak efficiency is usually around 50-60% load (on most psus). 

Then shouldn't I go with an 850W? as 60% of 850 = 510

 

A less efficient psu just pulls more power to do it . 

So, if I am not the one paying my power bill and if we assume I have access to free, unlimited power (Return of the Jedi reference) then bronze, gold, platinum, ect PSU's are an irrelevant statistic? 

[79wjd]

So, if I am not the one paying my power bill and if we assume I have access to free, unlimited power (Return of the Jedi reference) then bronze, gold, platinum, ect PSU's are an irrelevant statistic? 

Yes/No. Platinum PSUs are usually better than gold, which are usually better than silver, which are usually better than bronze. However the efficiency rating does NOT automatically make the psu good. 

 

Anyway, I would still save a whole lot of money and get the EVGA G2 750w psu as it's one of the best 80+gold PSUs with an exceptionally good (and long) warranty.

 

 

Actually a 620w would be more efficient. Due to a system usually not being oc'ed to the wall and at 100% load 24/7, an as small as possible psu is generally more efficient than one that's larger than necessary. 

And that depends how often the system is at load vs. idle. A system would have to be at idle much longer than at load to make up the efficiency difference -- A couple % more/less efficient at 150w~ power draw is a lot less than at 500w~ draw. 

[MegaDave91]

 

So, if I am not the one paying my power bill and if we assume I have access to free, unlimited power (Return of the Jedi reference) then bronze, gold, platinum, ect PSU's are an irrelevant statistic? 

Good way to sum it up, although there can be correlation between build quality and the more precious the metal (rating).

[Emceeschw3pp3]

Anyway, I would still save a whole lot of money and get the EVGA G2 750w psu as it's one of the best 80+gold PSUs with an exceptionally good (and long) warranty.

Well, the PSU in that build is fanless and that was my reason for selecting that particular PSU

[79wjd]

Well, the PSU in that build is fanless and that was my reason for selecting that particular PSU

You won't hear the G2 anyway, in addition to having a very quiet fan, it also has an eco mode where the fan won't kick in until it's needed.

[Emceeschw3pp3]

You won't hear the G2 anyway, in addition to having a very quiet fan, it also has an eco mode where the fan won't kick in until it's needed.

quite fan is still louder than no fan.

[MegaDave91]

Well, the PSU in that build is fanless and that was my reason for selecting that particular PSU

I honestly doubt you'll hear the fan anyway.

[79wjd]

quite fan is still louder than no fan.

Quiet fan, which doesn't kick in and will still be FAR quieter than every other fan in the case anyway.*

[WoodenMarker]

Then shouldn't I go with an 850W? as 60% of 850 = 510

So, if I am not the one paying my power bill and if we assume I have access to free, unlimited power (Return of the Jedi reference) then bronze, gold, platinum, ect PSU's are an irrelevant statistic? 

No. The system rarely ever use it's peak power draw. That's why it's called the peak. Even at full gaming load, the power draw would be lower than synthetic loads.

Higher efficiency = less heat 

And that depends how often the system is at load vs. idle. A system would have to be at idle much longer than at load to make up the efficiency difference -- A couple % more/less efficient at 150w~ power draw is a lot less than at 500w~ draw. 

Actually, it's the other way around. The system would need to be at load much more often to be more efficient than a lower one since. The system probably won't ever hit 500w power draw in realistic loads. Normal loads are going to be much lower. 

[79wjd]

No. The system rarely ever use it's peak power draw. That's why it's called the peak. Even at full gaming load, the power draw would be lower than synthetic loads.

Higher efficiency = less heat 

Actually, it's the other way around. The system would need to be at load much more often to be more efficient than a lower one since. The system probably won't ever hit 500w power draw in realistic loads. Normal loads are going to be much lower. 

True....I guess it also depends how the user actually uses it.