[breatheasy9er]

hi im in the process of my first build and have a few questions...

if i get an xfx radeon hd 4870 1g, do you think a corsair 400w would be ok..

itll be on a gigabyte 790gx mobo, phenom ii x3 720BE, and WD caviar black 640g hdd. this will all be in an antec 900(4 fans)

i do plan on overclocking and eventually adding an additional 4870.

i guess what im asking is.... would the 400w be capable of powering another card in the future. ive been reading how the card requires two 6-pin slots but am unsure which psu will work with this.... plus another in the future.

im on a budget but will wait and save if it means a better computer... just nothing overkill

any help appreciated

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The wattage isn't important.
It's perfectly possible to have a 1000w PSU that can't run specific graphics cards because they don't have enough amperage.
You need to look at what's called the rails on the power supply. The rails are effectively different voltages, +3.3, +5, +12, -5 and -12. These days you only need to worry about +3.3, +12 and +5, the rest are obsolete in today's systems. +12 is sometimes subdivided as well.

Typically most modern day cards require a certain amount of amps on the +12v rail. If this isn't satisfied, you can feed it as many watts as you want but it won't work. Therefore the important value for certain graphics card is the amps on the 12v rail and theoretically it's possible to run a decent card on a 350w power supply. Not recommended (preferably at least 450w) but certainly possible.

[Neil Jones]

The wattage isn't important.
It's perfectly possible to have a 1000w PSU that can't run specific graphics cards because they don't have enough amperage.
You need to look at what's called the rails on the power supply. The rails are effectively different voltages, +3.3, +5, +12, -5 and -12. These days you only need to worry about +3.3, +12 and +5, the rest are obsolete in today's systems. +12 is sometimes subdivided as well.

Typically most modern day cards require a certain amount of amps on the +12v rail. If this isn't satisfied, you can feed it as many watts as you want but it won't work. Therefore the important value for certain graphics card is the amps on the 12v rail and theoretically it's possible to run a decent card on a 350w power supply. Not recommended (preferably at least 450w) but certainly possible.

[iammykyl]

Hi.


Go to any major psu sites, eg Antec, look under support, psu calculater. Fill out all the fields for the componants you will be using, you will then get a reccomended psu. Then you can see if it suits the card specifcations you have selected as in Neil Jones post.

Regards.

iammykyl.

[breatheasy9er]

i appreciate both of your comments. i didnt know that... it does make sense.

i was recommended this(fixed) at another forum... this one also

what are your thoughts? haven't heard much about the brand, but it meets all my requirements... and the reviews were really good.

and im also considering two 4670's... seeing as how thatd still be cheaper than one 4870

Edited by breatheasy9er, 09 November 2009 - 11:54 PM.

[Ferrari]

breatheasy9er, your link is broken, can you try again?

Things to consider when buying a PSU are:

• What are the +12v amps? (The higher the better)
• How many PCI-E connectors does it have?
• Is it 80 plus certified? (Meaning, 80% or higher effecient)

Corsair is the best PSU manufacturer, many don't argue that. Others that stand out are OCZ, Seasonic, Antec, Coolermaster. Neil is 100% correct in what he said.

[breatheasy9er]

fixed it

[Ferrari]

Thanks. That PSU is not 80 Plus certified, so that means "Fail". The last thing you want to do is send unstable power to all of your valuable/costly components. Some would even argue that the PSU is the single most important piece of equipment in a computer. Clean stable power is very good.

I don't think you have mentioned a budget, but here is a 650watt Corsair PSU. It has a single +12v Rail at 52amps. <---really nice. It is also 80% efficient = Win. It has 2, 6pin connectors for the 4870's. Even has 6+2 pins actually, just in case you ever need it in the future. $99.

EDIT: Just saw your other link to the OCZ one. It is pretty nice, but if you really plan to run two 4870's in the future, I think you may want/need more like the Corsair one I already mentioned. If you just want to run one 4870, I'd definitely say that OCZ one is a winner.

Edited by Ferrari, 10 November 2009 - 12:04 AM.

[breatheasy9er]

yeah... definitely either the OCZ or your corsair. i like them both, but... regrettably yes... im on a budget. but i do want the best for my money.... and more importantly my time. it may take a loan but ill get it done.. haha.

and i really am grateful for the help man.

Edited by breatheasy9er, 10 November 2009 - 12:47 AM.