Hey PSU expert's can u tell me is this enough

[Allan_01]

I choose this PSU because its cheap..


http://www.kitguru.net/components/power-supplies/zardon/fsp-aurum-cm-series-gold-650w-psu-review/6/

planned build

x6 1100T stock voltage OC

x2 HD6870 no OC

will be this PSU enough ???

 

[Rugger]

A system with two HD 6870s in CF requires a 700W PSU with at least 44A on the 12V rails and four 75W 6-pin PCIe connectors; amperage on the 12V rails is more important than watts. The FSP Aurum Gold with 50A on the 12V rails is sufficient for your build.

 

[alexinnes]

+1 ^

 

[truegenius]

^^+1
you need at least 500w on 12v that means around a minimum of 45A on 12v for 2xhd6870 and thuban overclocked
add some more watts for other stuff (dvd drive, hdd, ram, mobo, fans etc) thus that 650w psu is good for you

 

[13thmonkey]

I choose this PSU because its cheap..


http://www.kitguru.net/components/power-supplies/zardon/fsp-aurum-cm-series-gold-650w-psu-review/6/

planned build

x6 1100T stock voltage OC

x2 HD6870 no OC

will be this PSU enough ???

You did read this on the first page didn't you?

Load regulation of the FSP power supply didn’t impress us, with the +5V output in particular causing a concern, at 400W it dropped to 4.86V, falling further to 4.67V at full load, which is below the recommended ATX specifications of 4.75V. The +12V output dropped to 11.77V at full load which isn’t quite as concerning, but nonetheless is still far from ideal. The +3.3V output dropped to 3.22V at full load.

And you'll be using it nearer to full load than most.

 

[truegenius]

^+1

 

[ram1009]

You're asking all the wrong questions. Instead of looking for the cheapest lowest wattage PSU you can use you should be doing exaxctly the opposite. The quality of the PSU you choose will become a factor in everything you do with your rig and especially it's longevity. And, using a larger PSU is the cheapest insurance policy you'll ever buy. Personally, I try never to run my PSUs over 50% of capacity.

 

[ram1009]

A system with two HD 6870s in CF requires a 700W PSU with at least 44A on the 12V rails and four 75W 6-pin PCIe connectors; amperage on the 12V rails is more important than watts. The FSP Aurum Gold with 50A on the 12V rails is sufficient for your build.

"amperage on the 12V rails is more important than watts. "

Watts = volts X amps so for any given voltage watts vary in proportion to amps. To say one is more important than the other is wrong and misleading especially to those with little knowledge of electronics.

 

[Rugger]

"amperage on the 12V rails is more important than watts. "

Watts = volts X amps so for any given voltage watts vary in proportion to amps. To say one is more important than the other is wrong and misleading especially to those with little knowledge of electronics.

The intent of that statement is to say that amperage on the 12V rails is more important than the wattage rating for the PSU. The reason is that the primary loads on modern PCs are the CPU and the GPU and both of these components draw the majority of their power from the 12V rails. If you argue that the wattage rating is just as important as the amount of amperage on the 12V rails, then would you rather have a 750W PSU with 45A on the 12V rails or a 650W PSU with 55A on the 12V rails?

 

[ram1009]

The intent of that statement is to say that amperage on the 12V rails is more important than the wattage rating for the PSU. The reason is that the primary loads on modern PCs are the CPU and the GPU and both of these components draw the majority of their power from the 12V rails. If you argue that the wattage rating is just as important as the amount of amperage on the 12V rails, then would you rather have a 750W PSU with 45A on the 12V rails or a 650W PSU with 55A on the 12V rails?

"amperage on the 12V rails is more important than watts" This is a direct quote from your post. Now you say that your reference to watts meant total PSU watts. I would argue your are wrong either way. PSU wattage is the number most often referenced in PSU specs and is a composite of all the wattages of the various voltages. Your statement now infers that 12 volt wattage or amperage is more important than wattages of the other voltages which I completely disagree with. Any voltage that has insufficient wattage or is poorly regulated will cause problems. All voltages are equally important. Telling less knowledgeable people to focus on the 12 volt rail is wrong.

 

[Rugger]

Now you say that your reference to watts meant total PSU watts.

I was simply trying to clarify the context behind the statement. I think you are right in that I need to be more clear in how I say it.

I would argue your are wrong either way. PSU wattage is the number most often referenced in PSU specs and is a composite of all the wattages of the various voltages.

You certainly have the right to argue that. PSU wattage IS the most frequently referenced rating when discussing PSUs and that's exactly why I highlight the importance of amperage on the 12V rails. The overall wattage rating of a PSU doesn't really tell you if that PSU will be able to handle the components in your system. It's a good estimate and the easiest way for GPU mfrs to inform customers in specifications requirements. Why do I reference amperage on the 12V rail as the most important factor in the recommendations I give? It's because 80% of the power consumed in modern PCs comes from the 12V rails: http://www.silentpcreview.com/article1245-page4.html and power distribution/usage has remained consistent since the SPCR's last power distribution article done in 2005.

Any voltage that has insufficient wattage or is poorly regulated will cause problems. All voltages are equally important.

I absolutely agree with you here; each voltage rail needs good regulation and sufficient power available for system components.

Telling less knowledgeable people to focus on the 12 volt rail is wrong.

You never answered my question...Would you rather have a 750W PSU with 45A on the 12V rails or a 650W PSU with 55A on the 12V rails? Why?

 

[ram1009]

Now you say that your reference to watts meant total PSU watts.

I was simply trying to clarify the context behind the statement. I think you are right in that I need to be more clear in how I say it.

I would argue your are wrong either way. PSU wattage is the number most often referenced in PSU specs and is a composite of all the wattages of the various voltages.

You certainly have the right to argue that. PSU wattage IS the most frequently referenced rating when discussing PSUs and that's exactly why I highlight the importance of amperage on the 12V rails. The overall wattage rating of a PSU doesn't really tell you if that PSU will be able to handle the components in your system. It's a good estimate and the easiest way for GPU mfrs to inform customers in specifications requirements. Why do I reference amperage on the 12V rail as the most important factor in the recommendations I give? It's because 80% of the power consumed in modern PCs comes from the 12V rails: http://www.silentpcreview.com/article1245-page4.html and power distribution/usage has remained consistent since the SPCR's last power distribution article done in 2005.

Any voltage that has insufficient wattage or is poorly regulated will cause problems. All voltages are equally important.

I absolutely agree with you here; each voltage rail needs good regulation and sufficient power available for system components.

Telling less knowledgeable people to focus on the 12 volt rail is wrong.

You never answered my question...Would you rather have a 750W PSU with 45A on the 12V rails or a 650W PSU with 55A on the 12V rails? Why?

You need to do the math before giving examples: 55 x 12 =660. Never the less, I get your point. More 12VDC is always better but it's not an excuse to ignore the other rails which is how I think some may interpret your comments. All the numbers are important. None should be passed over just because one is great.

 

[InvalidError]

All the numbers are important. None should be passed over just because one is great.

What are the differences between low-end and high-end PCs?
- CPUs, almost entirely powered off 12V rails, 70-150W
- GPUs, almost entirely powered off 12V rails, 120-250W, possibly x2 or x3
- RAID, 5-10W off 12V for spindle and actuator, 2-3W off 5V for electronics
- SSD, only 1-3W off either 3.3V or 5V rail
- fans, 1-10W off 12V rail
- water pump, 10-20W off 12V rail
- audio card, 3-10W
- extra network card(s), 2-5W per port

90-97% of the extra load in a kitted-out high-end setup is off the 12V rail, a high-end system hardly uses any more power off the 3.3V/5V rails than a low-end one.

While the lower voltage rails should not be overlooked, overloading them is unlikely unless you either add large amounts of unusual 3.3V/5V loads or the 1000W PSU has worse 3.3V/5V ratings than good 450W PSUs do, which would be surprising.

 

[truegenius]

Would you rather have a 750W PSU with 45A on the 12V rails or a 650W PSU with 55A on the 12V rails?
Why?

give me both
because, you will pay the bill for me, since you offered

 

[Rugger]

give me both
because, you will pay the bill for me, since you offered

They're in the mail - enjoy!

 

[benikens]

You never answered my question...Would you rather have a 750W PSU with 45A on the 12V rails or a 650W PSU with 55A on the 12V rails? Why?

I dunno about you, but you didn't leave any wattage for 3V or 5V rails(on the 650W) which means the system wouldn't be able to power the other devices, in that case I would recommend ram1009 take the 750W PSU in your hypothetical situation however without context a PSU doesn't mean anything so perhaps it's for a doorstop in which case I'd be looking at a weight value instead.

OP: Determine the wattage range you need (In this case it's seems ~700W thought don't quote me on that I haven't calculated it) Then decide if you want to pay a premium for a modular PSU, Then decide what efficiency your after (just google 80+ certifications if your not sure) then once you've got yourself some basic requirements for your PSU look for the cheapest that meets those standards. If still unsure link it here for some more feedback.

 

[Rugger]

I dunno about you, but you didn't leave any wattage for 3V or 5V rails(on the 650W) which means the system wouldn't be able to power the other devices, in that case I would recommend ram1009 take the 750W PSU in your hypothetical situation however without context a PSU doesn't mean anything so perhaps it's for a doorstop in which case I'd be looking at a weight value instead.

Point taken...let me know if you can find a 650W or 750W PSU that meets the ATX12V standard and can't meet the limited 3.3V and 5V requirements placed on it by modern PCs.