Watts?

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byteninja2

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Okay, apparently my psu is different than the picture, I think.Here is what my PSU says:130w max on +3.3v and +5v and 300w on +12V1 and +12V2 and 9.6w on -12V and 10w on +5Vsb, if you need any more info like amps, let me know.
 
Okedokey

Okedokey

Well-Known Member
OMG, what?

Im sorry but a cheap-ass PSU with 12A on CPU and `15A on 12V+2 MAX is completely and utterly not able to support any discrete graphics card.

Derate that bad boy and you will see that the 300W 12V max rating is more like 240W. You add even the crappest discrete GPU, add summer = bang.

You need a new PSU.
 
wolfeking

wolfeking

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I don't think so. And I would go with bigfella on this. He is much more knowledgeable about power supplies.

You can only use one rail at a time. With that little power, your 6 pin will only be on one rail. And at 240 watts you have to take off RAM power, DVD drives, HDDs, and CPU power as well as your fans. Your looking probably around 110 or so after everything comes off (just guessing) and that is on a cold day with no heat in teh room.
 
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byteninja2

banned
Why do temps matter?Plus, my case keeps components cool like a freezer.7 80 mm fans does a lot, and I have a HUGE case, so great airflow.
 
wolfeking

wolfeking

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the hotter it is the less efficient the power supply is. a 500 watt @ 30* will be less, probably 420 at 80*.
No matter how much air you put into it, it will never be as cool as room temp.
 
Hyper-Threaded

Hyper-Threaded

New Member
byteninja2 said:
Why do temps matter?Plus, my case keeps components cool like a freezer.7 80 mm fans does a lot, and I have a HUGE case, so great airflow.
Click to expand...

Get a new power supply. Its $40 for a 430watt corsair. Dont cheap out on this one. And you dont need to WTC bigfella, he knows what he is doing. Trying to see if other people says your good is not going to help.
 
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byteninja2

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Hmmm...Okay.But, still running very cool.So, lets say -20w.So here is what I think I could do with everything at full load:So, here:30w for hdd, 10w for memory, and 30w for baord (i doubt this, what do you think?), and 20w for psu temp, i have no cd rom.Fans use 25w max i think, 3w a fan i think.So,115w.Than, which rail has 120w, 12V2 or V1?And, i did need to say wtc to bigfella.He is quite knowladable, but I dont think he understands some pretty powerfull gpus can use just above 100w, not everything requires 800w like his 580 tri sli setup.I have no idea why he said only the worst gpus can use that little power.I CANNOT get a new psu right now.
 
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MyCattMaxx

MyCattMaxx

Active Member
Just go for it and when it blows up don't say that you weren't warned.

Beating on this isn't going to make it better with that PS.
 
Okedokey

Okedokey

Well-Known Member
byteninja2 said:
WTC?The best gpu to date uses 200w.Oh, @wolfe, can I run a graphics card using both rails?
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It works like this mate:

Power supply units that are rated at MAX, is another way of saying it will go bang if you try to load 300W.
Temperature increases resistance in a linear relationship
Resistance increases heat, and resistance causes heat (this is how electrical fires start).
A viscious circle is produced.

The higher the resistance the higher the inefficiency (the PSU is consuming more than its fair share).

The higher the heat output of the PSU, the higher the case temp gets, the lower the efficiency.

Basically if that PSU is rated at max 300W on the 12V rail (70% efficiency) you would derate it by 4W every 1 degree (C) above 25oC. Inside a stressed computer in summer that can easily be 60oC (ie 35oC above rating), meaning you derate it by 4 x 35 = 140W.

That means that in summer your PSU will only be able to provide 160W on the 12V rail MAX!! ie bang if you want more

Meanwhile, the ATX design standard means that 12V+1 is dedicated to the CPU. This means that half the 160W (ie 80W) is electrically isolated to only provide power to the CPU (ie. not available elsewhere regardless of load).

That means you have 80W of power 6.6A for your whole 12V system minus the cpu.

Insufficient.
 
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byteninja2

banned
I am trying to ask a question, and you guys are saying how bad my psu is.Is the 120w on the +12V1 or V2?Listen to this:My system was just using my psu with all most exactly the same specs, just about 20w lower power draw.My gfx card currently takes 70w.Also, i thought you guys said the CPU goes off a whole different rail, the one that says 120w?
 
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Okedokey

Okedokey

Well-Known Member
Already answered it if you had've read my respone. 12V+1 is CPU and if you understand basic ohms law, its 10A x 12V = 120W therefore it has to be the 12V+1 which is 10A, beacuse computers run at 12V.
 
wolfeking

wolfeking

banned
max output is 12 times what your amps are when it was built and at the temp that it is designed for. the 10 amp rail will be 120 max and teh 15 amp rail is 180 max. Minus age and tempature.

YOu need a new PSU before you get anything else.
 
Hyper-Threaded

Hyper-Threaded

New Member
byteninja2 said:
I am trying to ask a question, and you guys are saying how bad my psu is.Is the 120w on the +12V1 or V2?
Click to expand...

Like cattmaxx said, If you dont want to take our advise, go ahead. No one is stopping you. You want to use your power supply so bad, just do it. If it blows up, its not on us.
 
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