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HD 6770 on a 370w PSU?

Last response: in Graphics & Displays
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March 15, 2012 12:06:59 AM

Hi forum,

I was gonna order this card. My machine's cpu only draws 65w not oc'd.
I have 3 hd I assume pull 10-15w a piece. 1 optical combo 30w? 4gb ram 1w per gb not oc'd.?.? So that's roughly 150w.

The TPD for the 6770 is 108w (source). So that's about 260 total...leaves me over 100w to play with.?.? Am I cool getting this card?

I don't know much about PSUs but it says max 370@ +12 18a, +12 15a

It's a HP server psu that ran an AMD Opteron quad core.

Thanks!

More about : 6770 370w psu

March 15, 2012 12:15:13 AM

http://images10.newegg.com/BizIntell/tool/psucalc/index...

Instead of guessing try this wattage calculator and see what it says. The manufacturers web page for a similar model card says it requires a 400w psu for that card to be used in a Pc. Now with 370w you are close so it may work or it may not , it's going to depend on how your psu is made and by who. You haven't listed the brand of the card or the psu so your asking us a question and your not providing all of the info , at this point I'm just guessing.
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March 15, 2012 12:39:28 AM

That calculator isn't always accurate. I gave the model of the card with the easy link: "this card" above. The model of the PSU is not important if you have the specs which I posted above as well; 370w max 12v rails and 18&15amps. Moreover, the manufactures recommendations for this type of scenario are always overkill.
I already got my answer though from other forums,which is what I already suspected that it in fact, will. Thanks!
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March 15, 2012 2:48:31 AM

The brand and make of the psu is actually very important when determining reliability.
With that said you have plenty of headroom for the 6770 and it should work as long as your psu can put out said wattage in a stable fashion.
The 7750 might be another option at 55w with the same power as the 6770 and better dx11 support.
It also requires no external power connector
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March 15, 2012 3:26:38 AM

Reliability yes, but not just to see if it can push something. Ok I'll check out the 7750..especially if it draws less pwr :) 

Thanks!

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March 15, 2012 3:39:59 AM

No prob; the 7750 is what i would go with if i had a power restriction and 100 ish budget
55w peak use without any power connector as powerful as the 6770 w/ better dx11 support smells like win in your situation
Check out the toms review they have all the details for you with real world performance to help you make your decision
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March 15, 2012 3:48:08 AM

edit: the 7750 has a slower core clock at 800 mhz - the 6770 runs at 850mhz. Also the 7750 only has 512 Stream Processing Units while the 6770 has 800. Reference
Dust proof fan, good reviews and only takes up one slot not 2. I think I'll stick with that.
The Dx11 I don't care about with this particular machine here..it's only running xp64 so can't take advantage of it :( 
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March 15, 2012 4:59:55 AM

For a system using a single Radeon HD 6770 graphics card AMD specifies a minimum of a 450 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 one 6-pin PCI Express supplementary power connector.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Continuous Amperage Available on the +12V Rail(s) is the most important factor.

The HP 370W ATX power supply, with its combined +12 Volt continuous current rating of 25 Amps and with no PCI Express supplementary power connectors, is electrically sufficient to power your system configuration with a single Radeon HD 6770. You will need to use a dual 4-pin Molex peripheral to 6-pin PCIe power adapter cable.
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March 15, 2012 5:16:31 AM

Which is why i would recommend the 7750 instead
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March 15, 2012 6:13:10 AM

@ko88: I thought the the combined +12v amps of my psu was 33 (18 + 15)? In any case thanks for the info! The 6770 comes with the 6 pin adapter too :) 

@FlintIronStagg: He was saying my psu IS 'electrically sufficient' to power my system and the 6770. Why are you still pushing the 7750 when it's a lower performance card lol?
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March 15, 2012 6:20:39 AM

Would a HD 7750 work on my 350w PSU from DELL?

I have a Dell 8100 Studio XPS and I would like to know, would a HD 7750 work on my 350w PSU from DELL?
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March 15, 2012 6:22:30 AM

bumgoatz said:
@ko88: I thought the the combined +12v amps of my psu was 33 (18 + 15)? In any case thanks for the info! The 6770 comes with the 6 pin adapter too :) 

@FlintIronStagg: He was saying my psu IS 'electrically sufficient' to power my system and the 6770. Why are you still pushing the 7750 when it's a lower performance card lol?

On the power supply's label it should also specify the maximum combined wattage for the two +12V rails which is 300 Watts. That works out to 25 Amps maximum using Ohm's law.
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March 15, 2012 7:54:36 AM

True. You need to be very careful when working with multirail PSU's. The max total of 12 volt current is almost always less than the sum of each of the rails.

That is why I prefer single rail power supplies even though they technically violate the PSU ATX specifications.
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March 15, 2012 11:14:08 AM

Yea I see it does say that on the label for two +12 @300w (12p & 12d). Does that mean I will only have 300w available from the psu when running the 6770? Or am I not to be concerned with that? What does 12'p' and 12'd' stand for?
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March 15, 2012 11:57:11 AM

Or you could just not worry about it and get an HD 7750 for the same price and performance.

Bumgoatz - it doesn't matter how many stream processors or what the clock speed is - newer architecture always trumps the older. Check any benchmarks in any game; the HD 7750 very nearly matches the HD 5770/6770 in every game. And it would run on a generic 250w PSU just fine.
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March 15, 2012 1:47:06 PM

What the lable is saying (300 Watts max combined and 18A vor v1 and 15 amps max for V2)
If you draw 17 Amps on V1 then V2 is limited to ONLY 8 Amps, not 15 Amps
If you draw 14 Amps on V2 then V1 is limited to 9 Amps.

While each +12 V rail has a max listed capability, the Combined amperage is limited to the 300 Watts.

This can further be complicated by the fact that the max is 370 Watts, So if the power for all other Rails (+5V, +3.3 V, ect) exceeded 70 Watts than that would further limit the available power for the +12 V rail (or visa versa).

A typical setup using the 6770, running furmark will draw around 300 -> 350 Watts. Loaded with a game somewhate less. My recommendation for a "quality" psu is a Minimum of 20% higher thant the max. 300 + 20% = 360 W, 350 + 20% = 420 Watts.
I never go by wattage calculatores. (1) I look for system reviews showing power consumption for the given Video card, and/or (2) stick my watt meter ($15) and add 20% min to what is drawn at the wall.
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March 15, 2012 9:49:43 PM

@Jesstermanster: I hear ya, but the "just about matching" performance is not 'better'. Plus the 6770 is cheaper with a 20 buck rebate :) . And if it's so great why is nobody buying it? The power demand difference is minimal anyway = 6770 @108 and the 7750 @90 (source Tom's HW)..just 18w.


@RetiredChief

I would love to get a new PSU and I understand what you are saying, thank you. But I can't afford it right now. Fyi, I've been running a card for the past 3 years almost 24/7 on this psu that draws 75w with a proc that drew 95w without 1 single hitch. Now I have a 65w proc. I'm gonna roll the dice and not split hairs here. 85% say (other forums too) I'll be able to use this card with no problems. None of this is in stone and I also understand the no one REALLY KNOWS. And from my layman's pov it seems reasonable to roll the dice. If it doesn't work I'll go from there. I'll let you know if it blows up :) 

Thanks again!
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March 15, 2012 10:35:42 PM

No the 7750 is 55w max (that's why it needs no power connecter) - the link you have is for their entire system with the 7750 at idle. But yeah either of those cards should be fine on your PSU. The card will max out at POST, so you'll know immediately if your PSU can handle your system with the increased load.
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March 15, 2012 11:10:34 PM

^^ agreed and as far as pushing the 7750 over the 6770;
you are looking at paper specs not real world benches where they perform very closely together.
If you want the 6770 Thats fine but before you spat at other peoples opinions or ideas remember Youre the one asking for help and.it has been offered.
The 7750 uses 55w max. If it used close to 100 as you were saying it would need an external 6 pin power plug to support anything above 75w which is what the pcie slot provides.
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March 15, 2012 11:46:54 PM

Who's spatting? I'm just making educated inquiries to get the biggest bang for my buck and not stress out my system too much in the process. This has been very educational and I' m grateful for all the input. Lighten up bro ;) 
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March 15, 2012 11:48:55 PM

Best answer selected by bumgoatz.
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