Graphic Cards 6850 Crossfire on Corsair CX500

You think you know more then kindly explain this calculation.....

vaibhav1 said:
because if your PSU is not 80 plus then you are already putting a lot of strain on it, the psu's which are not 80 plus they can only be good upto 50 - 60 percent more than that can cause problem or it may even blow up, so you have 500 watts 50% of 500 is 250 so just think that single 6850 is more than enough for that PSU.
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you are making a mess of calculations here and asking what wrong you are saying... Come on man you are saying if a 500W PSU is 50% efficient then it will give out only 50/100*500=250w??? :facepalm:

Let me explain:

Acc to definition, Output power/input power * 100 = efficiency (%) The definition itself clears the whole doubt you have. Efficiency in our case is given, output power is given...So it calculates the input power only... How will you determine output power from efficiency and this equation..??/ You have any answer??? You shouldnt have any, and thats my bet...

Now If I manufacture a PSU and rate it as capable of giving 500W output and 80% efficient, then does the definition say that my PSU is capable of delivering 80% of my rated output???? i.e 80/100*500=400W ?? Answer is NO.

It means it will suck in (100%-80%)=20% more power from AC socket to convert it to 500w. (approximate values, true values can differ according to various losses) Oh yes... Do you know what losses are??

(The above are full load calculations i.e if your system is sucking out 500w from 500w PSU, ideal case, not practical)

So get your basics right about efficiency and power calculations

I hope I am clear. Further explanation can be given on request
 
chiragsthakur said:
You think you know more then kindly explain this calculation.....

you are making a mess of calculations here and asking what wrong you are saying... Come on man you are saying if a 500W PSU is 50% efficient then it will give out only 50/100*500=250w??? :facepalm:

Let me explain:

Acc to definition, Output power/input power * 100 = efficiency (%) The definition itself clears the whole doubt you have. Efficiency in our case is given, output power is given...So it calculates the input power only... How will you determine output power from efficiency and this equation..??/ You have any answer??? You shouldnt have any, and thats my bet...

Now If I manufacture a PSU and rate it as capable of giving 500W output and 80% efficient, then does the definition say that my PSU is capable of delivering 80% of my rated output???? i.e 80/100*500=400W ?? Answer is NO.

It means it will suck in (100%-80%)=20% more power from AC socket to convert it to 500w. (approximate values, true values can differ according to various losses) Oh yes... Do you know what losses are??

(The above are full load calculations i.e if your system is sucking out 500w from 500w PSU, ideal case, not practical)

So get your basics right about efficiency and power calculations

I hope I am clear. Further explanation can be given on request
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Ok my friend, two 6850's will consume about 300 - 340 watts power on max load so what you are saying is that this CX 500 watts can handle the crossfire X without any problems isn't it, so that means the problem is solved he doesn't need's a better power supply. Very good job.

just one more thing can you tell me what power supply is needed for 6990 it consumes about 600 - 650 watts as told in Anandtech bench mark's .?
 
:facepalm:

Now kill me :chair:

Dont you understand what we are trying to say?? We are not debating about CX500 here, we are debating on what you have commented (I have quoted your comment above)...

No one has said that CX500 is enough to handle 6850's in CF...just go on the first page and read my comment rather than trying to showoff...

Seriously but you should carry this tag with you :new:
 
chiragsthakur said:
:facepalm:

Now kill me :chair:

Dont you understand what we are trying to say?? We are not debating about CX500 here, we are debating on what you have commented (I have quoted your comment above)...

No one has said that CX500 is enough to handle 6850's in CF...just go on the first page and read my comment rather than trying to showoff...

Seriously but you should carry this tag with you :new:
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yes man seriously i am new here, but as you where explaining the input output power i thought that this CX500 is sufficient for two 6850's.

well please answer my question, what power supply is needed for 6990 it consumes about 600 - 650 watts as told in Anandtech bench mark's .?
 
Vaibhav, you may want to cool off first. Don't get personal.

I'm going to be as gentle as possible.

Let me put this down in a simple, logical way and I hope you will understand. I hope my example is not too complicated, so I will try and bring it down to the right level.

Now.

Like I said, there are enough PSUs without certification that will power those cards.

PCP&C 600 will do it - and that's a 4-year old supply.

So will an Antec TP750 from 3 years ago (well before 80+ appeared). For sure my Antec TP550 easily ran a SLI setup with near the same level of power consumption.

How does one even explain this?

Assume your system draws 450W under load. The setup the TS had is roughly about that, maybe a bit less.

Assume you want a supply that operates at about 80% of its rated maximum when you subject it to this load.

You need a supply that delivers 450/0.8, which is 562W. Say 550W, to round it off.

You need a supply that will deliver 550W at its output with stable voltages. This has absolutely nothing to do with efficiency. A supply which is able (keyword: able, not just stated) to do this will do it whether it has 70% efficiency or 99% efficiency.

Of course, in the case of a supply that is 70% efficient at this load it will be consuming 650W from the mains and a supply that is 95% efficient will consume 473W, a difference of 180W. So it will show up in your electric bill.

If you wanted the supply to stay in the 60-70% load band, you would need a 700W supply. Why this band? Because a typical PC PSU is most efficient at about 55-60% load. which does not mean it is not capable of delivering 80%, but it would be the most beneficial from a power consumption point of view.

You are completely confused, not understood a difference between power output rating and efficiency. A good supply will deliver on both. A reasonable supply will deliver on one of these two. A piece of shit will deliver neither.

And to answer your acerbic comment, yes, I can design and make a PC power supply, I do have the right level of experience. Want to push your luck? And no one said the CX500 can or should be used to power the setup.

You need to be able to get the red tint off your eyes and read all the replies, read them twice.

You are spreading FUD around 80+ and power output which are actually two very different things.

We can't have nonsensical information being put up on these forums.

We don't want people to be misled reading up wrong information. There is a reputation of these forums.

You are not doing your research properly, understanding thing completely the wrong way and then getting aggravated when people point out your mistakes.

If you can cool off, you will see there is much to learn. I am sure there are things you know far, far better than anybody, but for sure power supply fundamentals aren't it.
 
It does not make sense increasing the thread, unnecessarily, yup there were few things that added to our knowledge, but for the thread starter , your psu may not be sufficient for the sli setup, you may try but it may involve risk.
 
what power supply is needed for 6990 it consumes about 600 - 650 watts
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650W is total system power consumption with a 6990, not the consumption of the card itself. A good 850-900W unit is required, but you could get by with a very high quality 750W unit, say the AX750.

Edit: Just looked over the charts and AT is clear that the 6990 consumes:

490W (stock card, full load)

545W (OC card, full load)

550W (stock card, Furmark)

680W (OC card, Furmark)

If you don't run Furmark on an OC card a good 750W unit is enough. I was suspicious when I figured my 6970CF runs absolutely fine on a TX750, not the world's best power supply. A 6990 draws less than my cards.
 
cranky said:
Vaibhav, you may want to cool off first. Don't get personal.

I'm going to be as gentle as possible.

Let me put this down in a simple, logical way and I hope you will understand. I hope my example is not too complicated, so I will try and bring it down to the right level.

Now.

Like I said, there are enough PSUs without certification that will power those cards.

PCP&C 600 will do it - and that's a 4-year old supply.

So will an Antec TP750 from 3 years ago (well before 80+ appeared). For sure my Antec TP550 easily ran a SLI setup with near the same level of power consumption.

How does one even explain this?

Assume your system draws 450W under load. The setup the TS had is roughly about that, maybe a bit less.

Assume you want a supply that operates at about 80% of its rated maximum when you subject it to this load.

You need a supply that delivers 450/0.8, which is 562W. Say 550W, to round it off.

You need a supply that will deliver 550W at its output with stable voltages. This has absolutely nothing to do with efficiency. A supply which is able (keyword: able, not just stated) to do this will do it whether it has 70% efficiency or 99% efficiency.

Of course, in the case of a supply that is 70% efficient at this load it will be consuming 650W from the mains and a supply that is 95% efficient will consume 473W, a difference of 180W. So it will show up in your electric bill.

If you wanted the supply to stay in the 60-70% load band, you would need a 700W supply. Why this band? Because a typical PC PSU is most efficient at about 55-60% load. which does not mean it is not capable of delivering 80%, but it would be the most beneficial from a power consumption point of view.

You are completely confused, not understood a difference between power output rating and efficiency. A good supply will deliver on both. A reasonable supply will deliver on one of these two. A piece of shit will deliver neither.

And to answer your acerbic comment, yes, I can design and make a PC power supply, I do have the right level of experience. Want to push your luck? And no one said the CX500 can or should be used to power the setup.

You need to be able to get the red tint off your eyes and read all the replies, read them twice.

You are spreading FUD around 80+ and power output which are actually two very different things.

We can't have nonsensical information being put up on these forums.

We don't want people to be misled reading up wrong information. There is a reputation of these forums.

You are not doing your research properly, understanding thing completely the wrong way and then getting aggravated when people point out your mistakes.

If you can cool off, you will see there is much to learn. I am sure there are things you know far, far better than anybody, but for sure power supply fundamentals aren't it.
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My apologies my friend if i have said something wrong, i just suggested the guy to get a decent PSU and you just popped in just trying to prove me wrong that NO vaibhav is wrong i don't agree with him then you started explaining me things, i think the main agenda of this post is to tell the guy what to do, as i did the same now i said get a 600 watts psu that is good i am wrong because i suggested him to get a 80+ PSU now what does that means.?
 
I would use PSU of the likes of Corsair TX850 V2 for this... And what do you achieve by asking this question and that too with yourself having half knowledge about power calculations??
vaibhav1 said:
yes man seriously i am new here, but as you where explaining the input output power i thought that this CX500 is sufficient for two 6850's.

well please answer my question, what power supply is needed for 6990 it consumes about 600 - 650 watts as told in Anandtech bench mark's .?
Click to expand...
 
chiragsthakur said:
I would use PSU of the likes of Corsair TX850 V2 for this... And what do you achieve by asking this question and that too with yourself having half knowledge about power calculations??
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why do you think like that? it was just a question.
 
This wasnt needed then coz its 100% wrong...You should have mentioned the exact model number and name of PSU rather than spreading misinformation....
vaibhav1 said:
because if you'r PSU is not 80 plus then you are already putting a lot of strain on it, the psu's which are not 80 plus they can only be good upto 50 - 60 percent more than that can cause problem or it may even blow up, so you have 500 watts 50% of 500 is 250 so just think that single 6850 is more than enough for that PSU.
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Really?

vaibhav1 said:
because if you'r PSU is not 80 plus then you are already putting a lot of strain on it,
Click to expand...
 
chiragsthakur said:
This wasnt needed then coz its 100% wrong...You should have mentioned the exact model number and name of PSU rather than spreading misinformation....

Really?
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My friend you miss understood me i was just trying to say that 80+ can handle more load rather than non 80+.

see what i am trying to explain is a 80+ PSU can run on 100% load for about 24 hours (it is just an example) but non 80+ can't do that it will die.

now correct me if i am wrong.
 
Efficiency of a PSU defines power consumption by the PSU to covert it into required output power. So its related to Electricity bill my friend.You will have to pay less bill if using a 80+ PSU as comapred to 70% efficient PSU.. Any PSU if kept loaded continuously for a very long duration of time is bound to get faulty in near future or die...... Whether it be non 80+ rated or 80+ rated..... The difference in quality of components used in a PSU decides when it will die or give problems...Thats why we dont suggest Zebronics 800w PSU over Corsair/seasonic 800 watts PSU...Its not because the Corsairs and seasonic are 80+ rated its because the quality of components used is top notch and so they are 80+ too ... did you get it now??
 
chiragsthakur said:
Efficiency of a PSU defines power consumption by the PSU to covert it into required output power. So its related to Electricity bill my friend.You will have to pay less bill if using a 80+ PSU as comapred to 70% efficient PSU.. Any PSU if kept loaded continuously for a very long duration of time is bound to get faulty in near future or die...... Whether it be non 80+ rated or 80+ rated..... The difference in quality of components used in a PSU decides when it will die or give problems...Thats why we dont suggest Zebronics 800w PSU over Corsair/seasonic 800 watts PSU...Its not because the Corsairs and seasonic are 80+ rated its because the quality of components used is top notch and so they are 80+ too ... did you get it now??
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yes now i got it.
 
you just popped in just trying to prove me wrong
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Don't mix conversations.

I did not prove you wrong. I was straightening out this statement:

you need 600watts or 500watts with 80 plus certification
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Which was based on erroneous logic:

psu's which are not 80 plus they can only be good upto 50 - 60 percent more than that can cause problem
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And my reply to your post said:

^^Correct, and wrong
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Because your "No" was the correct answer, but the rest of the logic was all wrong.

You have to remember PSUs have existed long before 80+ came into the picture, and even then there were good PSUs, great PSUs and nonsense PSUs. 80+ only governs one aspect of the PSU and is not a guarantee of other performance parameters.
 
Some really interesting posts here. Let me get another doubt clarified.

Cranky: You have stated in simple words that 80+ efficiency is not equated to clean/stable power. Now let me put it this way say a power supply is 80+ gold certified. Would I be wrong in assuming the supply would provide good clean power at 80% load? If no, how does a PSU manage to achieve high efficiency at the expense of stable power?
 
^^What I said was that 80+ does not necessarily mean clean/stable power. It only mean efficiency.

I could for example, have a power supply that is 80+ Platinum certified, and have voltage regulation and ripple and noise close to ATX limits or even exceed them. The supply could fail crossload tests, and be noisy and hot. A 1000W supply with 80+ Gold, for example, would still need to dissipate close to 150W at full tilt. It is easy for me to design a supply that skimps on thermals. Or on output ripple suppression. Or both.

High efficiency is simply the efficiency of the converters used in the design. If I want to design a supply that meets 80+ Gold and I still have a cost target, trust me it can be done.

The catch is brand reputation. A Corsair supply which is marketed as a high-end supply will conscience-driven, cost a lot to make (and buy) and be high quality and efficient. So yes, a Corsair AX750 will beat the pants off (say) an Enermax supply of the same rating and with the same certifications. But that is not because of the certifications.

It is also possible to design an excellent power supply that does not meet 80+. A lot of older supplies will drive newer systems just fine, except they will consume a lot of power doing so.

Always keep in mind 80+ is certification. Not a holy grail of some sort. If this were true each and every PSU manufactured and meeting the 80+ standard would perform identically. We all know this is not true.

Let me ask you another question. If you had two refrigerators, both rated 4 stars, would you say they would perform identically under all sorts of conditions?
 
cranky said:
Don't mix conversations.

I did not prove you wrong. I was straightening out this statement:

Which was based on erroneous logic:

And my reply to your post said:

Because your "No" was the correct answer, but the rest of the logic was all wrong.

You have to remember PSUs have existed long before 80+ came into the picture, and even then there were good PSUs, great PSUs and nonsense PSUs. 80+ only governs one aspect of the PSU and is not a guarantee of other performance parameters.
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Ok guys i got it seriously i got it.:)

actually it was me with wrong information and i thought that i was wright Damn me.:ashamed:

I hope you forgive me for that.?
 
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