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How many watts for a PSU do I need?

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January 2, 2012 4:54:43 PM

Im doing some upgrading down the road so I want to be prepared. This is what I have on the finished build once hard drive prices go down....

case- LIAN LI PC-Q08B
Hard drive - 6 sata 7200 drives in raid 0 and 1 120gb drive to boot windows
cpu- A8-3850 2.9ghz
gpu- His 6870
Ram- Vengence CMZ8GX3M2A1866C9 2x4gb 1866mhz
psu- ?
mobo- asus f1a75 I Deluxe
drive- dvd

Im looking for a reliable PSU but I also dont want to pay a fortune for it either. I was looking at this one OCZ ModXStream Pro 700W. Im not sure if thats too many watts. I might over clock my cpu a little bit but not much. Any suggestions would be appreciated. Thanks

More about : watts psu

January 2, 2012 5:20:29 PM

a 3850, while a very good APU, isn't the best CPU. a phenom II 955 would be faster. and since its a black edition it can easily be overclocked. and you dont end up with on die graphics being wasted. oh and its cheaper.

a 500w would be cutting it close so i recommend jumping to a 600w
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a c 147 ) Power supply
January 2, 2012 5:52:28 PM

AMD reconnends a 500w psu for a 6870. Other parts are relatively unimportant.
http://www.amd.com/us/products/desktop/graphics/amd-rad...

Since you have a few extra hard drives, I suggest a 550-650w psu.

My short list of quality psu's would include Antec, Seasonic, PC P&C, XFX, and Corsair.
A cheap psu is false economy.

Here is a suitable corsair 600w unit for $50 after rebate:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
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Related resources
a b ) Power supply
January 2, 2012 6:03:54 PM

I'd recommend an Antec Earthwatts 500...

...and definitely a Sandy Bridge CPU (probably an i3 to stay at the same budget. You're wasting your money with AMD, unless you go for an older Phenom II. But then you don't have an upgrade path.

Unless you already have those parts you listed...
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a c 1200 ) Power supply
January 2, 2012 6:17:38 PM

For a system using a single Radeon HD 6870 graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 24 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

The following modular power supply units all meet or exceed the requirements:

Corsair Enthusiast Series Modular TX550M (CP-9020001-NA) for $89.99 ($79.99 after mail-in rebate card)
• +12 Volt continuous current rating of 45 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• OEM: CWT (Channel Well Technology)
• Warranty: 5 Years
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

PC Power and Cooling Silencer MK III PPCMK3S500 500W for $79.99 ($59.99 after mail-in rebate card)
• +12 Volt continuous current rating of 38 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• OEM: Seasonic
• Warranty: 5 Years
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


PC Power and Cooling Silencer MK III PPCMK3S600 600W for $89.99 ($69.99 after mail-in rebate card)
• +12 Volt continuous current rating of 46 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• OEM: Seasonic
• Warranty: 5 Years
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
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a b ) Power supply
January 2, 2012 6:26:51 PM

OCZ actually is a good PSU brand. My list is Seasonic, Antec, OCZ, Enermax, XFX, PC Power & Cooling, silverstone and corsair.
As for wattage look at this its far more accurate than other PSU calculators.
http://extreme.outervision.com/psucalculatorlite.jsp
He can't get the corsair you listed because it only has two PCI-E connectors and if he wants to be able to CF in the future he needs four. Also do get the Phenom ll and overclock to 3.6-3.8 GHz (if you want AMD not Intel that is). If you want to be able to upgrade in the future then consider an AM3+ motherboard instead of the AM3.
Now for the PSU I'd get. Would be one of these, even 600w would be more than enough.
First the two Antec, both good would pay the $5 more for the modular PSU.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Good modular OCZ.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
For SilversverStone I included two in case you don't think 600w is enough, although I think its plenty.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Two XFX for the same reason.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

What is your budget?
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January 2, 2012 6:33:16 PM

no such thing as too many watts or too powerful.the power supply is the heart of your system,never cheap out,always buy from a quality company as geofelt has suggested.,read reviews and do some research on what ever you decide..single 12v rails are the best.

if you need 500W,buy a 700W....etc...If you buy "just"enough.it will always be running at ,say 90%,thus producing more heat and shorter lifespan.
I am/may be the exception,but I haven't used less than 1000W in the last 5 years.even with all that i am running,I'll bet my PSU never breaks a sweat,and I can always upgrade to whatever I want in the future.
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a c 1200 ) Power supply
January 2, 2012 6:33:40 PM

andrewcarr said:
OCZ actually is a good PSU brand. My list is Seasonic, Antec, OCZ, Enermax, XFX, PC Power & Cooling, silverstone and corsair.
As for wattage look at this its far more accurate than other PSU calculators.
http://extreme.outervision.com/psucalculatorlite.jsp
He can't get the corsair you listed because it only has two PCI-E connectors and if he wants to be able to CF in the future he needs four. Also do get the Phenom ll and overclock to 3.6-3.8 GHz (if you want AMD not Intel that is). If you want to be able to upgrade in the future then consider an AM3+ motherboard instead of the AM3.
Now for the PSU I'd get. Would be one of these, even 600w would be more than enough.
First the two Antec, both good would pay the $5 more for the modular PSU.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Good modular OCZ.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
For SilversverStone I included two in case you don't think 600w is enough, although I think its plenty.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Two XFX for the same reason.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

What is your budget?

Tell me how the OP will be able to do 2-way CrossFireX on an ASUS F1A75-I DELUXE motherboard that has only one expansion slot and its the 1 x PCIe 2.0 x16 slot?

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January 2, 2012 6:34:42 PM

jessterman21 said:
I'd recommend an Antec Earthwatts 500...

...and definitely a Sandy Bridge CPU (probably an i3 to stay at the same budget. You're wasting your money with AMD, unless you go for an older Phenom II. But then you don't have an upgrade path.

Unless you already have those parts you listed...



your comment is so flawed its rather funny.Ahh..i see,you own a dell.
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a b ) Power supply
January 2, 2012 6:45:00 PM

For a dual 6870 system he only needs about 500w. The lowest I listed was 600w and most of the time your PC is using far less than the max. If you only use 1000w PSU then the efficiency is just less (although not a considerable amount) and you pay a premium when you buy the PSU.
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a b ) Power supply
January 2, 2012 6:47:14 PM

I figured he would change the motherboard and CPU. We mentioned the i3 or i5 as the best option but the Phenom ll x4 would also be good.

Edit- didn't look at his case. Will he even be able to fit one 6870 in it?
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a c 1200 ) Power supply
January 2, 2012 6:51:49 PM

andrewcarr said:
I figured he would change the motherboard and CPU. We mentioned the i3 or i5 as the best option but the Phenom ll x4 would also be good.

Did you also suggest a new larger case to go along with that motherboard change?

The OP hasn't responded to any of the suggestions as of yet.
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January 2, 2012 7:39:57 PM

andrewcarr said:
For a dual 6870 system he only needs about 500w. The lowest I listed was 600w and most of the time your PC is using far less than the max. If you only use 1000w PSU then the efficiency is just less (although not a considerable amount) and you pay a premium when you buy the PSU.



I also payed a premium for all the other components.Like i said,i may be an exception to the rule,but i wont rely on subpar psu's on any of my systems.not to mention my psu will never get hot,let alone warm.

But ya,where is the OP.....hes got a lot of great suggestions here.
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a b ) Power supply
January 3, 2012 1:37:42 AM

Earnie said:
your comment is so flawed its rather funny.Ahh..i see,you own a dell.

Really don't see what's so flawed about my suggestion Earnie, so please enlighten us all. OP said "Im looking for a reliable PSU but I also dont want to pay a fortune for it either." The Earthwatts 500 is cheap, reliable, well beloved and will run the OP's system easily.

Cheap shot. Yes I've got a Dell - didn't know jack about computers 3 years ago, and don't have the coin to fund a full build. There isn't a part in it besides the mobo that I haven't upgraded, and it's got decent bones. Also, most don't have the funds for high-end parts - we go for best bang for the buck.

Which brings us back to the OP - what's your budget, Vanilla Ice? Also, that is one tight squeeze...
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a b ) Power supply
January 3, 2012 2:19:42 AM

andrewcarr said:
didn't look at his case. Will he even be able to fit one 6870 in it?

For real. I didn't check that case either, and OP will need more molex connections than most PSUs have... Wait, 7 storage drives??? And a gaming card will not fit with that many HDDs in that case. Definitely will want a modular PSU as well, that little box has no room for clutter.
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a c 1200 ) Power supply
January 3, 2012 2:25:09 AM

It could be an HTPC and the raid array is in its own separate drive tower.
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January 3, 2012 5:02:43 AM

Whoa thanks for all the replies guys. Yes this is an HTPC computer thats why I ended up with cpu I bought. I would rather try to keep the case some what small, but have plenty of storage for media files. I think the case should be ok with the extra video card I have at hand. I currently have a Silverstone Sugo Series SG05BB-450 Mini-ITX Case and I was able to fit the videocard in there without any problems, but Im OCD on my wiring. I figure I also wanted to play some games on it as well on my 50in hdtv so my plan was to hook it up with a xbox 360 controller. This is a dumb question but If I wanted to buy a 1200 watt psu it wouldnt overkill the system or anything? I have a left over psu but its only 550 watts would that be good enough? Thanks again guys
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January 3, 2012 5:10:57 AM

I honestly dont have a budget I was just looking for something reliable. I just wanted to get a better psu because eventually I will add a video card and more HDDs just of matter of cash.
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January 3, 2012 5:37:53 AM

never mind about the HIS 6870 the CPU can only crossfire with HD 6670. 6570 and 6450. Looks like im getting a HD 6670
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January 3, 2012 6:37:24 AM

word2yamutha said:
never mind about the HIS 6870 the CPU can only crossfire with HD 6670. 6570 and 6450. Looks like im getting a HD 6670


Well you could add a discrete card in, it just wouldn't crossfire. Obviously you won't be fitting any huge cards or SLI in this build though so the 6670 crossfire is probably fine. The system WITHOUT 6 hard drives will take less than 400 watts even with the 6670 so your 550W should be fine for now. With all those hard drives it's probably more like 600W+ so a 700W would be justifiable. 1200 is serious overkill, you'd never fit enough stuff in that box to take that much. I'm not sure you'd be able to fit all those drives in when you take all the cabling into consideration, but you're probably looking for a modular PSU to get rid of unneeded cabling. I don't see where your boot drive goes with the 6x RAID either.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

on the overkill end

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

if you went with 4x RAID and a boot drive + DVD

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January 3, 2012 9:40:27 AM

the boot drive will be a 120gb ssd drive the case has 6 3.5 in bays and 1 2.5 for an ssd.
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a b ) Power supply
January 3, 2012 11:49:49 AM

ko888 said:
For a system using a single Radeon HD 6870 graphics card AMD specifies a minimum of a 500 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 24 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

The following modular power supply units all meet or exceed the requirements:

Corsair Enthusiast Series Modular TX550M (CP-9020001-NA) for $89.99 ($79.99 after mail-in rebate card)
• +12 Volt continuous current rating of 45 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• OEM: CWT (Channel Well Technology)
• Warranty: 5 Years
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

PC Power and Cooling Silencer MK III PPCMK3S500 500W for $79.99 ($59.99 after mail-in rebate card)
• +12 Volt continuous current rating of 38 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• OEM: Seasonic
• Warranty: 5 Years
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


PC Power and Cooling Silencer MK III PPCMK3S600 600W for $89.99 ($69.99 after mail-in rebate card)
• +12 Volt continuous current rating of 46 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• OEM: Seasonic
• Warranty: 5 Years
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


+1
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January 3, 2012 12:26:20 PM

If you can afford it take a Corsair HX650, you will be good for crossfire (if that motherboard supports it)
Otherwise a Coolermaster GX-450 is more than ample,
its got 32 or 35a on 12V rail so thats way more than the required 24a
To be on the safe side a GX-550 for multiple hard drives but I don't think you'll need it.
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a b ) Power supply
January 3, 2012 1:18:56 PM

kinggraves said:
Well you could add a discrete card in, it just wouldn't crossfire. Obviously you won't be fitting any huge cards or SLI in this build though so the 6670 crossfire is probably fine. The system WITHOUT 6 hard drives will take less than 400 watts even with the 6670 so your 550W should be fine for now. With all those hard drives it's probably more like 600W+ so a 700W would be justifiable. 1200 is serious overkill, you'd never fit enough stuff in that box to take that much. I'm not sure you'd be able to fit all those drives in when you take all the cabling into consideration, but you're probably looking for a modular PSU to get rid of unneeded cabling. I don't see where your boot drive goes with the 6x RAID either.

+1

Also, he's talking about hybrid Xfire with his APU, everyone.
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a c 147 ) Power supply
January 3, 2012 1:37:17 PM

word2yamutha said:
never mind about the HIS 6870 the CPU can only crossfire with HD 6670. 6570 and 6450. Looks like im getting a HD 6670


I love the lian li Q08 case, but it is a ITX case which means only one pcie-X16 graphics slot. No dual card sli is possible.
Not that I think that is a great idea anyway. You can but a very strong single graphics card like the GTX590, or the new 7970 which is overkill for a single monitor anyway.
If you used something like a GTX570, now, or in the future, you should be able to play most games very well on a 50" 1080P monitor.

Here is what EVGA recommends for their graphics cards:

GTX550ti needs 400w with 24a on the 12v rails plus one 6-pin PCI-E power lead.

GTX560 needs 450w with 24a on the 12v rails plus two 6-pin PCI-E power leads.

GTX560Ti needs 500w with 30a on the 12v rails plus two 6-pin PCI-E power leads.

GTX570 needs 550w with 38a on the 12v rails plus two 6-pin PCI-E power leads.

GTX580 needs 600w with 42a on the 12v rails plus one 6-pin and one 8-pin PCI-E power lead.

GTX590 needs 700w with 50a on the 12v rails plus two 8-pin PCI-E power leads or 4 6-pin power leads.

It is not wrong to overprovision the psu a bit. It will run quieter when it is in the most efficient middle third of it's range.
I use a Seasonic X750 gold rated psu with a GTX580.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

The fan does not ever have to turn on. I expect that if I ever want to upgrade to the stronger new 28nm graphics cards, they will still use the same amount of power. And, in a small form factor case, modular is of some advantage.
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a c 1200 ) Power supply
January 3, 2012 7:54:19 PM

word2yamutha said:
Whoa thanks for all the replies guys. Yes this is an HTPC computer thats why I ended up with cpu I bought. I would rather try to keep the case some what small, but have plenty of storage for media files. I think the case should be ok with the extra video card I have at hand. I currently have a Silverstone Sugo Series SG05BB-450 Mini-ITX Case and I was able to fit the videocard in there without any problems, but Im OCD on my wiring. I figure I also wanted to play some games on it as well on my 50in hdtv so my plan was to hook it up with a xbox 360 controller. This is a dumb question but If I wanted to buy a 1200 watt psu it wouldnt overkill the system or anything? I have a left over psu but its only 550 watts would that be good enough? Thanks again guys

There is a drawback with the Lian Li PC-Q08B in terms of the physical length/depth of the power supply that it can handle without having to lose both of the 3.5 inch drive cages for the six HDDs.

A 1200 Watt power supply will have a length/depth of 180mm ~ 200mm (7.1 inches ~ 7.9 inches).

The Lian Li PC-Q08B will handle power supplies with a maximum length/depth of 140mm (5.5 inches) without having having to lose the 3.5 inch drive cages for the six HDDs.

What is the make and model of your left over 550 Watt power supply unit?

If it has a combined +12 Volt continuous current rating of 22 Amps or greater it will be sufficient to power a system with a single Radeon HD 6670. Just make sure its length/depth doesn't exceed 140mm (5.5 inches) so that you can use the six 3.5 inch drive bays.
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