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I hate to ask this....psu question..

C

Chappie

Senior member
Alright...here goes...and I hate even bringing this up. but...

I'm running an Asus A8n5x motherboard (basic nforce4 board) with the following:
Opty 144 at 2.5
1 gig corsair ram
soundblaster soundcard
evga 6800gs video card
1 basic dvd burner
1 dvd rom
2 ide hard drives ( I could get by with only one)
and 3 casefans
running on this FSP power supply: http://www.newegg.com/Product/Product.asp?Item=N82E16817104953

My question is this...could I replace the 6800gs card with a 7000 series nvidia card or possibly a 1900 series ati card WITHOUT replacing my psu??

I know this type of question is tiresome...but I need some advice.

thanks,

Chappie
 
If you are thinking of a PCI Express 16 card, get the 7600GT KO from eVGA. It derives all its power from the PCI bus, meaning it does not have a separate power connector to the psu. The minimum requirements stated on the eVGA site are 400 watts and 18 amps. Note that your psu has double rails and can supply a total of 18 + 16 = 34 on the 12V rails, so you are good to go.

But what you have to consider is will the 7600GT make a significant improvement over your current card. I can't answer that.

-Bob
 
You have 25 amps on the 12v rail, so you should be alright with a 7600GT. I wouldn't chance a card from the 1900 series, however.
 
Your Fortron will easily power a 7950GT, any X1900 series card, or 8800GTS.
 
Originally posted by: Chappie
8800 GTS??? that would be nice...but I have doubts about that.
Click to expand...
There's no doubt that your doubts stem from people that recommend high wattage psu's on a regular basis. A quality psu w/ 30A (which yours has) on the +12v rail(s) will be more than adequate for the cards that I listed.
 
Originally posted by: Chappie
8800 GTS??? that would be nice...but I have doubts about that..

any other opinions??

thanks,

Chappie
Click to expand...

I run an 8800GTS on a Seasonic 380 with no issues. People think computers need way more power than they do.

Edit - just for some reference, a system with a Core 2 Duo X6800 + 8800GTS only pulls 244w under load:
http://anandtech.com/video/showdoc.aspx?i=2873&p=7

Total draw of the 8800GTS can not be over 150 watts which is 12.5 amps MAX due to it only having one PCI-E power connector. In reality it is likely closer to 10A max under load.
 
Just wanted to bump this up...anyone else with some opinions on this??? It seems there is alot of conflicting information when it comes to power supplies. I've been to jonnyguru's site as well. Alot of great info. there, but I'm a bit confused still.

Other thoughts are welcome.

thanks,

Chappie
 
A good quality, strong PSU with more amps on the 12V rail is more important than sheer wattage. My PSU is 580W but I don't use anywhere near that; I have it because I bought it to replace the crappy 500W one I bought that was too weak to power my graphics card (X1950XT). Just compare the specs of the card you're interested in with the amps delivered by the PSU you're thinking of.
 
Originally posted by: John
Your Fortron will easily power a 7950GT, any X1900 series card, or 8800GTS.
Click to expand...

John's advice is solid. Your power supply is sufficient to power any single card, save for the 8800GTX. :thumbsup:
 
You shouldn't have any problems with that psu. I have a very generic 400 watt psu that came out of an old linkworld case. It only has 15 amps on the 12v+, and it runs the system in my sig no problem with 5 80mm fans. I would say you're not gonna have any problems with that psu, depending on the reliability of this brand.
 
Originally posted by: John
Originally posted by: Chappie
8800 GTS??? that would be nice...but I have doubts about that.
Click to expand...
There's no doubt that your doubts stem from people that recommend high wattage psu's on a regular basis. A quality psu w/ 30A (which yours has) on the +12v rail(s) will be more than adequate for the cards that I listed.
Click to expand...

Where are you getting this baloney? You can't add the two rails together to get total output. The spec sheet notes a maximum of 300W on the +12V rails, which divided by the 12V means 25amps total, as a previous poster correctly stated.

That's OK, but not a lot of headroom for a XTX or GTS.
 
you see??,

this is what has always confused me...the back and forth arguments and the real world examples of people stating what their system is and how they are running it on certain PSU's. Who is telling the truth?? I'm sure some people exaggerate, but science doesn't lie either...

so the question remains...could I run an nvidia 7950 card?? or maybe an x1950 Pro or x1900xt?? the mind boggles!! LOL What about a refurbished 7800GT?? I know many of the x1900 specs suggest 30 amps on the +12 volt...so I guess I'm out of luck there. but what about the Nvidia cards...

thanks,

Chappie
 
The x1950 pro doesn't eat nearly as much power as an X1900 or X1950 XT(X) and it's also a great card for the price. If you're also looking for graphics card suggestions I'd say get an x1950 pro.
 
Originally posted by: Chappie
you see??,

this is what has always confused me...the back and forth arguments and the real world examples of people stating what their system is and how they are running it on certain PSU's. Who is telling the truth?? I'm sure some people exaggerate, but science doesn't lie either...

so the question remains...could I run an nvidia 7950 card?? or maybe an x1950 Pro or x1900xt?? the mind boggles!! LOL What about a refurbished 7800GT?? I know many of the x1900 specs suggest 30 amps on the +12 volt...so I guess I'm out of luck there. but what about the Nvidia cards...

thanks,

Chappie
Click to expand...

If you do a little bit or research it's not that boggling at all.

This link has already been provided to you above (perhaps you choose to ignore it?) but in it you will see the power consumption with 8800GTX is under 300 watts for entire system.

Your FSP is 400 watts with 25A dedicated to 12v power; whats so hard to understand?
 
what's so confusing??

what is the most important thing..total watts or amps on the +12 volt line. I guess I'm on information overload from reading other sources of information. From what I've read the most important thing is the +12 volt...

If that's the case...then why do other sources (i.e. ..people) suggest that my psu would be fine running a card that requires more than what my +12 volt produces. Do these people not know what they are talking about??? Maybe I'm being thick or naive.

just curious.

thanks,

Chappie
 
Originally posted by: Chappie
what's so confusing??

what is the most important thing..total watts or amps on the +12 volt line. I guess I'm on information overload from reading other sources of information. From what I've read the most important thing is the +12 volt...

If that's the case...then why do other sources (i.e. ..people) suggest that my psu would be fine running a card that requires more than what my +12 volt produces. Do these people not know what they are talking about??? Maybe I'm being thick or naive.

just curious.

thanks,

Chappie
Click to expand...

Ok there is a lot of information to process but it's manage once you separate fact from opinion...

12v power is more important then total wattage. Since both the CPU and GPU draw most of their power from 12v sources a good modern PSU should have about 3/4 of it's power dedicated to 12v rails since thats the power that will be realistically usable. For example your 400 watt FSP has 300 of it's total 400 watts on 12v rails which is exactly 3/4.

It also doesn't help that a lot of it isn't really based on anything at all. Example; both nVidia and ATi both make wattage recommendations that sadly have nothing to do with what the actual card will actually draw in terms of power.

Instead these recommendations are more of way covering their bases since these cards draw up to 90% of their power from 12v rails and many PSU manufactures (Thermaltake) are still selling PSU that have half of their wattage in the 5v and 3.3v rails instead of the 12v where it should be.

So in essence you could have two 400 watt PSUs, PSU A with 50% of it's power dedicated to 12v and PSU B with 80%. Both are 400 watt PSUs but PSU A would struggle to power a modern high-end system since it only has 200 watts (16.5A) available to 12v power while PSU B would hardly break a sweat since it has 320 watts (26.5A) available.

I rambled that off fairly quickly hopefully it made sense. For further reading and a better understanding check out this excellent SPCR write up about power distribution: "Power Distribution within Six PCs".
 
For most people, needing to know how many amps on which voltage is too confusing. That's why video card manufacturers state "you need XXX watts" because it is an easier number to digest. They specify larger numbers than many people actually need because that way they can reasonably cover most power supplies, as in most XXX (let's say 400W) power supplies have enough +12v to run a given system with a certain video card.

Power supply companies don't make this easy on you either. How do they get such a wattage number? Well, you would think that a 400W power supply can put out 400W all at the same time, but that is not the case. How some companies figure out the numbers is that they measure each voltage individually, then add up all the numbers for a nice fat wattage. However, most power supplies can't handle the maximum power output to all voltages all at the same time. The "better" power supplies can to some degree.

Also, multiple rails on +12v is confusing because as pointed out, they just don't add up. Your PSU gives 18A and 16A. That's 34A, right? Wrong, as pointed out the manufacturer states that combined maximum is 25A. Why is that? Well, the whole +12v system can only handle 25A. Each "rail" can handle 18A and 16A on their own, but let's say you already peaked one at 18A, then you can only load 7A on the second.

"What does this all mean, Basil?"

Assuming good "quality" (that's a whole different discussion) and if the manufacturer didn't lie^H^H^H ahem, creatively market their power supply's ability to continuously sustain a given amount of power on a certain voltage... a moderate un-overclocked system with a modern mid-range CPU (not Prescott 😛 ), mid range GPU and a single hard drive may only need around 14-18A total on the +12v. High end overclocked CPU and GPU may need closer to 22-26A and dual high end GPUs may need closer to 30A or more. At this point we're talking about dual 8800GTX. Now, before somebody gets their pantsu tied up in knots, yes I pulled all those amperage numbers out of my azz. However, they are likely in the ballpark.
 
Operandi: I just spent nearly two hours reading the article 'Power distribution within Six PCs' and the related discussion posts.

Very interesting and it certainly cleared up a few things for me. I think I'll spend a little more time checking SPCR out.

-Bob
 
Yes, same for me Operandi...very nice article...I haven't read the forums posts concerning the article yet. I'm still at work..

thanks,

Chappie
 
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