Graphic Cards 6850 Crossfire on Corsair CX500
- Thread starter touzeen
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cyberwarfare
Galvanizer
You can search overclock.net and search the forums for the psu calculator
it will guide you to the best of its abilities
it will guide you to the best of its abilities
touzeen said:
The answer is no you need 600watts or 500watts with 80 plus certification.
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.
Correct, and wrong.
^^Output capability has nothing to do with efficiency certifications. They are entirely different things.
And I'm not sure where you get the idea that a non-certified PSU is good for only 50% of its capacity. Care to explain?
There are good PSUs and bad PSUs. Not all certified 80+ PSUs are great. Not all PSUs without 80+ certification are bad.
I would suggest spending time to update yourself about supplies.
To the original question:
At a purely theoretical level a 500W PSU is enough for to 6850s, with a CPU at stock frequencies. Each card needs around 130W, and a top-shelf CPU around 100W so a typical 500W supply will be loaded (theoretical maximum load) at about 80% after adding in fans, drives etc.
However
I wouldn't trust a low-cost supply like that one to be able to do it. You can do a bit of digging, and you'll see the CX500 has problem powering a single 5850, something it should be able to easily handle. A 5850 draws around 160W. You need to have about 260W of power to your GPUs alone.
OTOH I have seen a Tagan StoneRock 500 being used to test a 4870x2 (not long-term usage) and it worked just fine for the 6 hours or so it was used for. That card should have very similar power draw to two 6850s (or even more - it is close to 300W). Note the Stonerock did/does not carry 80+ certification. And it's not a supply I would recommend anyway.
I would look at a high quality 600W unit with the right connectors, just to err on the margin of safety.
cyberwarfare
Galvanizer
i would have to agree with cranky
the psu is a very critical part of the system and it is better to spend a bit more on something more reliable now rather than possible larger damages later
the psu is a very critical part of the system and it is better to spend a bit more on something more reliable now rather than possible larger damages later
chiragsthakur
Forerunner
cranky said:
i think the high quality PSU's comes with 80+ certification i my self is using 6950 on a crappy 600watts iball which is not 80+ and it runs fine while gaming and all the stuff but when i put extreme load on gpu like doing benchmarks my computer freezes, that's because it is not 80+, if i would have a 80+ certified 600watt's psu then it would run my pc smooth and nice, now what do you think a 600 what PSU is not capable of running a 6950? i think if it is 80+ certified then yes it will run like a charm.
Right. So for noobs like us, would you care to explain what 80+ certification is?
Your PSU is crappy because it is crappy. It is not because it is not certified. 600W is what the PSU wil deliver before blowing up.
All good PSUs usually have 80+ certification.
All PSUs with 80+ are not good PSUs.
iBall will never make a good PSU. 80+ or not.
We had 150W GPUs running in SLI and CF long, long before 80+ certification started.
We had PSUs that could run those kind of setups, and none of those had 80+ certification.
If your PSU is a piece of crap doesn't mean all PSUs at 600W with no 80+ certification are also crap.
80+ certification is efficiency of the psu, don't mess it up with how good a psu could be or loads it can take. I have used normal psu without , as well as 80+ certified psu.
If you have a 80+ psu , I can tell you it is efficient, will use efficient power. No wastage of electricity and stuff. But it may stop working as any other branded or non branded psu.
I would suggest a psu that had 80+ rating cause of its efficiency and power on each rail. Go by reviews mostly, it helps.
Correct me if I am wrong
Also for original question, you may require a better psu to run the cards.
If you have a 80+ psu , I can tell you it is efficient, will use efficient power. No wastage of electricity and stuff. But it may stop working as any other branded or non branded psu.
I would suggest a psu that had 80+ rating cause of its efficiency and power on each rail. Go by reviews mostly, it helps.
Correct me if I am wrong
Also for original question, you may require a better psu to run the cards.
vaibhav1 said:
80 PLUS is an initiative to promote energy efficiency in computer power supply units (PSU). It certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load, and a power factor of 0.9 or greater at 100% load. That is, PSUs will waste 20% or less electric energy as heat at the specified load levels, thus reducing electricity use and bills compared to less efficient PSUs. Sometimes rebates are given for manufacturers who use 80 PLUS-certified PSUs.
The efficiency of a computer power supply is its output power divided by its input power. The remaining power is converted into heat. For instance, a 600-watt power supply with 60% efficiency running at full load would draw 1000 W from the mains and would therefore waste 400 W as heat. On the other hand a 600-watt power supply with 80% efficiency running at full load would draw 750 W from the mains and would therefore waste only 150 W as heat.
For a given power supply, efficiency varies depending on how much power is being delivered. Supplies are typically most efficient at between half and three quarters load, much less efficient at low load, and somewhat less efficient at maximum load. Older ATX power supplies were typically 60% to 75% efficient. To qualify for 80 PLUS, a power supply must achieve at least 80% efficiency at three specified loads (20%, 50% and 100% of maximum rated power). However, 80 PLUS supplies may still be less than 80% efficient at lower loads. For instance, an 80 PLUS, 520 watt supply could still be 70% or less efficient at 60 watts (a typical idle power for a desktop computer).[7] Thus it is still important to select a supply with capacity appropriate to the device being powered.
It is easier to achieve the higher efficiency levels for higher wattage supplies, so gold and platinum supplies may be less available in consumer level supplies of reasonable capacity for typical desktop machines.
Typical computer power supplies may have power factors as low as 0.5 to 0.6.[8] The higher power factor reduces the peak current draw, reducing load on the circuit or on an uninterruptible power supply.
Reducing the heat output of the computer helps reduce noise, since fans do not have to spin as fast to cool the computer. Reduced heat and resulting lower cooling demands may increase computer reliability.[8]
The testing conditions may give an unrealistic expectation of efficiency for heavily loaded, high power (rated much larger than 300 W) supplies. A heavily loaded power supply and the computer it is powering generate significant amounts of heat, which may raise the power supply temperature, which is likely to decrease its efficiency. Since power supplies are certified at room temperature, this effect is not taken into account.[3]
80 PLUS does not set efficiency targets for very low load. For instance, generation of standby power may still be relatively inefficient, and may not meet requirements of the One Watt Initiative. Testing of 80 PLUS power supplies shows that they vary considerably in standby efficiency. Some consume half a watt[9] or less in standby with no load, where others consume several times as much at standby,[10] even though they may meet higher 80 PLUS certification requirement levels. Inefficiencies in generating standby power are magnified by the amount of time that computers spend turned off.
if noobs like us need more information go to google and do some research.
--- Updated Post - Automerged ---
deaddevil said:80+ certification is efficiency of the psu, don't mess it up with how good a psu could be or loads it can take. I have used normal psu without , as well as 80+ certified psu.
If you have a 80+ psu , I can tell you it is efficient, will use efficient power. No wastage of electricity and stuff. But it may stop working as any other branded or non branded psu.
I would suggest a psu that had 80+ rating cause of its efficiency and power on each rail. Go by reviews mostly, it helps.
Correct me if I am wrong
Also for original question, you may require a better psu to run the cards.
I agree with him. Nice one dude.
chiragsthakur
Forerunner
Efficiency is not what you are explaining it as..
AFAIK It has nothing to do with output of the PSU, its the amount of Power in watts your PSU sucks out of your AC socket to generate the needed output. And the output of your PSU depends on current on rail, temperature, quality of components used.
So instead of keeping yourself in wrong perception and misleading others you may well get your perception right
AFAIK It has nothing to do with output of the PSU, its the amount of Power in watts your PSU sucks out of your AC socket to generate the needed output. And the output of your PSU depends on current on rail, temperature, quality of components used.
So instead of keeping yourself in wrong perception and misleading others you may well get your perception right
chiragsthakur
Forerunner
Ok so for you get any generic PSU more than 50A on +12v rail and run 6850's in CF... And just tell me do you know anything about the temperature ratings of PSU's?? CX500 being 80+ is rated just a 30 deg.C and thats the reason we are not recommending it
cyberwarfare
Galvanizer
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