400 Watt PSU enough for 6950 or simular?

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NathanP2007

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Dec 17, 2007
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Long story short, im building a PC, the PC for many months (up to 7) will have a 8600GTS GPU in it, however when the time arrives the PC will get a 6950 (or if they are out, a 7xxx series card). However, the PSU that will be used for the PC is a 400Watt one.

Specifically the CORSAIR CMPSU-400CX 400W ATX12V V2.2 80 PLUS Certified Compatible with Core i7 Power Supply

http://www.newegg.com/Product/Produ...9008&cm_re=CMPSU-400CX-_-17-139-008-_-Product
 
NathanP2007 said:
Long story short, im building a PC, the PC for many months (up to 7) will have a 8600GTS GPU in it, however when the time arrives the PC will get a 6950 (or if they are out, a 7xxx series card). However, the PSU that will be used for the PC is a 400Watt one.

Specifically the CORSAIR CMPSU-400CX 400W ATX12V V2.2 80 PLUS Certified Compatible with Core i7 Power Supply

http://www.newegg.com/Product/Produ...9008&cm_re=CMPSU-400CX-_-17-139-008-_-Product
Click to expand...

I am going to tell you nope.

Check out the recent MSI HAWK review that the good people at HardOCP just did here.

http://www.hardocp.com/article/2011/04/25/msi_n560gtxti_hawk_video_card_review/9

Look at the power consumption figures there for the MSI and the 6950 as well, and you'll see what I mean. Most people have no idea that the PSU is the most important component in a build, because it is one of very few components in a system that can take out other stuff if it decides to blow. I don't know what your budget is, but please do not cheap out on the PSU. Also keep in mind that this is the power draw for a relatively bare bones system that they used to test on.
 
amdgamer said:
I am going to tell you nope.

Check out the recent MSI HAWK review that the good people at HardOCP just did here.

http://www.hardocp.com/article/2011/04/25/msi_n560gtxti_hawk_video_card_review/9

Look at the power consumption figures there for the MSI and the 6950 as well, and you'll see what I mean. Most people have no idea that the PSU is the most important component in a build, because it is one of very few components in a system that can take out other stuff if it decides to blow. I don't know what your budget is, but please do not cheap out on the PSU. Also keep in mind that this is the power draw for a relatively bare bones system that they used to test on.
Click to expand...

Thanks thats good info and reasoning. Do you have a article like the one you posted regarding Crossfired 6950's and their power draw? I have asked before if my 750Watt in my PC will handle CF 6950's and have gotten confirmations but doesn't hurt to double check.

If 750Watts isnt enough it wouldnt be the end of the world though, because 1: Im not sure if it will be worth it to buy a second 6950 and CF compared to waiting for a 7xxx series and buying one of those which might perform as well as two 6950's CF'ed. 2: When Ivy Bridge/Sandy Bridge-E comes out i might be building a new gaming rig, and for that i will be majorly future proofing/investing. Meaning i will be buying a 1000+Watt Modular PSU (assuming modular is just as reliable, havent researched that) when i build that new rig, so my PSU wont ever be a question again.

As for the 400W and skimping out. A few minutes after i posted this i remembered that the little brother to my PSU is in a PC i built a while ago and gave to my parents. I can pull that PC P&C 610W out of it and use that instead of the 400W. Then put the 400W into my parents PC. Problem Solved in that regards :)

The 610W: http://www.pcpower.com/power-supply/silencer-610-eps12v.html
My 750W: http://www.pcpower.com/power-supply/silencer-750-quad-black.html


UPDATE:

Lol you can agree or disagree but i guess this is sorta answering my own question.

Found this article: http://www.guru3d.com/article/radeon-hd-6950-crossfirex-review/14
Which says:
Radeon HD 6950 in CrossfireX

A second card requires you to add another ~160 Watts. You need a 650+ Watt power supply unit and if you use it in a high-end system a 800+ to a KiloWatt is recommended especially if you plan on any overclocking.

I wouldnt consider my system high end. My motherboard is a pretty basic LGA 775, i have 2 hard drives but getting a third (2TB Green though). My CPU isnt OC'ed, and i wouldnt be OC'ing my GPU's. So i think (tell me if you disagree) that i wouldnt fall into that "high end system" part. My parts are more medium end.
 
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I agree with them when i bought my psu I didnt know that it was the most important part and i honestly screwed myself becuz I now have to upgrade to do SLI with new gpus.. I now know to get a lot better of a psu.
 
I found this article here from HardOCP where they pit an Antilles 6990 against a pair of 6970's in CFX.

http://www.hardocp.com/article/2011/03/07/amd_radeon_hd_6990_antilles_video_card_review/8

Keeping in mind that this is the power draw at the wall for a very barebones system, it does appear that a good solid 750 watt PSU might be enough so long as you stick with overclocking the CPU's. Since this is the powerdraw at the wall for a pair of 6970's, you probably could also do some mild overclocking to the 6950's you are planning on and be okay. The problem though is that I am risk adverse and think that it will be pushing too close to the limit.

Since you mention that you will be running an LGA775 motherboard, i'm wondering whether you could properly take advantage of a pair of 6950's without hitting the CPU bottleneck. I think you may be better off just getting a single 6950 for now and waiting until you have a chance to upgrade the motherboard and processor before adding a 2nd one.

As far as modular PSU's go, they mostly just help with cable management since you can always unplug stuff from the PSU that isn't needed.

NathanP2007 said:
Thanks thats good info and reasoning. Do you have a article like the one you posted regarding Crossfired 6950's and their power draw? I have asked before if my 750Watt in my PC will handle CF 6950's and have gotten confirmations but doesn't hurt to double check.

If 750Watts isnt enough it wouldnt be the end of the world though, because 1: Im not sure if it will be worth it to buy a second 6950 and CF compared to waiting for a 7xxx series and buying one of those which might perform as well as two 6950's CF'ed. 2: When Ivy Bridge/Sandy Bridge-E comes out i might be building a new gaming rig, and for that i will be majorly future proofing/investing. Meaning i will be buying a 1000+Watt Modular PSU (assuming modular is just as reliable, havent researched that) when i build that new rig, so my PSU wont ever be a question again.

As for the 400W and skimping out. A few minutes after i posted this i remembered that the little brother to my PSU is in a PC i built a while ago and gave to my parents. I can pull that PC P&C 610W out of it and use that instead of the 400W. Then put the 400W into my parents PC. Problem Solved in that regards :)

The 610W: http://www.pcpower.com/power-supply/silencer-610-eps12v.html
My 750W: http://www.pcpower.com/power-supply/silencer-750-quad-black.html


UPDATE:

Lol you can agree or disagree but i guess this is sorta answering my own question.

Found this article: http://www.guru3d.com/article/radeon-hd-6950-crossfirex-review/14
Which says:
Radeon HD 6950 in CrossfireX

A second card requires you to add another ~160 Watts. You need a 650+ Watt power supply unit and if you use it in a high-end system a 800+ to a KiloWatt is recommended especially if you plan on any overclocking.

I wouldnt consider my system high end. My motherboard is a pretty basic LGA 775, i have 2 hard drives but getting a third (2TB Green though). My CPU isnt OC'ed, and i wouldnt be OC'ing my GPU's. So i think (tell me if you disagree) that i wouldnt fall into that "high end system" part. My parts are more medium end.
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Aus10 said:
I agree with them when i bought my psu I didnt know that it was the most important part and i honestly screwed myself becuz I now have to upgrade to do SLI with new gpus.. I now know to get a lot better of a psu.
Click to expand...

Yeah man, all of us learn at some point :)

The moral of the story is always to never ever cheap out on the PSU because it is so critical to the safety for your entire system. I get irritated when people put together incredible system builds only to cheap out on the PSU. The fact of the matter, is that PSU's are extremely affordable and close in price until you start getting into the 950watt+ territory at which point the price takes a significant jump.
 
amdgamer said:
I found this article here from HardOCP where they pit an Antilles 6990 against a pair of 6970's in CFX.

http://www.hardocp.com/article/2011/03/07/amd_radeon_hd_6990_antilles_video_card_review/8

Keeping in mind that this is the power draw at the wall for a very barebones system, it does appear that a good solid 750 watt PSU might be enough so long as you stick with overclocking the CPU's. Since this is the powerdraw at the wall for a pair of 6970's, you probably could also do some mild overclocking to the 6950's you are planning on and be okay. The problem though is that I am risk adverse and think that it will be pushing too close to the limit.

Since you mention that you will be running an LGA775 motherboard, i'm wondering whether you could properly take advantage of a pair of 6950's without hitting the CPU bottleneck. I think you may be better off just getting a single 6950 for now and waiting until you have a chance to upgrade the motherboard and processor before adding a 2nd one.

As far as modular PSU's go, they mostly just help with cable management since you can always unplug stuff from the PSU that isn't needed.





Yeah man, all of us learn at some point :)

The moral of the story is always to never ever cheap out on the PSU because it is so critical to the safety for your entire system. I get irritated when people put together incredible system builds only to cheap out on the PSU. The fact of the matter, is that PSU's are extremely affordable and close in price until you start getting into the 950watt+ territory at which point the price takes a significant jump.
Click to expand...

Well i do already have a 6950 on my 775 socket setup (see sig) but i get what your saying. Thanks for the info on the modular, considering the concept seems fairly new i just wasnt sure if it changed anything in regards to reliability and performance. Considering they dont, i definitely will get one on my next build cause like you mentioned, the ability to remove cables your not using is awesome.

Yeah from what you say and that article it does seem that my reliable well made 750W will cut it if i was to CF, however i dont love the idea (like you point to) running my PSU near its limit.
On the topic of a second card for Crossfire, this is speculative because it all depends on things i have no power over at the moment. Such as how the 7xxx series stack up against my 6950 and at what price (which would push me towards either CF'ing or buying a 7xxx series card). How long until i build my next PC (which depends on when IV/SB-E is released) and etc. But this info is good so thanks guys.
 
NathanP2007 said:
Well i do already have a 6950 on my 775 socket setup (see sig) but i get what your saying. Thanks for the info on the modular, considering the concept seems fairly new i just wasnt sure if it changed anything in regards to reliability and performance. Considering they dont, i definitely will get one on my next build cause like you mentioned, the ability to remove cables your not using is awesome.

Yeah from what you say and that article it does seem that my reliable well made 750W will cut it if i was to CF, however i dont love the idea (like you point to) running my PSU near its limit.
On the topic of a second card for Crossfire, this is speculative because it all depends on things i have no power over at the moment. Such as how the 7xxx series stack up against my 6950 and at what price (which would push me towards either CF'ing or buying a 7xxx series card). How long until i build my next PC (which depends on when IV/SB-E is released) and etc. But this info is good so thanks guys.
Click to expand...

My advice is to worry about your needs right now instead of worrying about the 7000 series. The problem with technology, is that something new is always coming around the corner and there isn't a thing we can do about it. Theoretically, you could end up waiting forever as there will always be something new coming out. Never discount the loss of happiness you will suffer right now due to your decision to wait for something new to come down the line. Those 6+ months before the 7000 series comes out is 6+ months that you can be enjoying the ultimate in graphics performance.
 
amdgamer said:
My advice is to worry about your needs right now instead of worrying about the 7000 series. The problem with technology, is that something new is always coming around the corner and there isn't a thing we can do about it. Theoretically, you could end up waiting forever as there will always be something new coming out. Never discount the loss of happiness you will suffer right now due to your decision to wait for something new to come down the line. Those 6+ months before the 7000 series comes out is 6+ months that you can be enjoying the ultimate in graphics performance.
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True i do not disagree at all. However because i already have a great rig with a AMAZING card, i am currently enjoying the fruits of my rig in full Res at highest settings. So i have that luxury of waiting till 7xxx series. If i was struggling with <30FPS in my games and was finnicky about lowering my settings...then i totally agree that you shouldnt wait 6+ months for the new thing while you play choppy games, just CF now and enjoy 60FPS.
 
NathanP2007 said:
True i do not disagree at all. However because i already have a great rig with a AMAZING card, i am currently enjoying the fruits of my rig in full Res at highest settings. So i have that luxury of waiting till 7xxx series. If i was struggling with <30FPS in my games and was finnicky about lowering my settings...then i totally agree that you shouldnt wait 6+ months for the new thing while you play choppy games, just CF now and enjoy 60FPS.
Click to expand...

Well, there ya go as you have your answer to your question :)

Since you have the performance that you want already, then that sort of helps out with your decision. Of course, it could be a while if you believe the rumors that ATI is originally going to start the 7000 series with the low end just to test out the new 28nm technology before going full in.
 
amdgamer said:
Well, there ya go as you have your answer to your question :)

Since you have the performance that you want already, then that sort of helps out with your decision. Of course, it could be a while if you believe the rumors that ATI is originally going to start the 7000 series with the low end just to test out the new 28nm technology before going full in.
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If thats true, its very well possible when games start coming out that make my 6950 work hard for 40+FPS (DX11 games probably) then Crossfire will look better and better. But for now, my performance is fantastic. The test will be seeing what FPS i get in BF3 and Crysis 2 when it gets its DX 11 patch. If 40+ still, i can probably wait out the possibility of 7000 series starting at low end. If more like 30...then CF here i come.
I cant knock AMD for starting low end in that case. PC gamers are the loudest when happy and loudest when pissed, so imagine if they started off mid-to-high end and 28nm didnt work how it was supposed to. Would be hell for AMD.
 
To answer both your questions, the CX400 can handle a modest system with a single 6950, and your 750W PSU can handle a pair of them without any issues whatsoever. I'd be more comfortable with something a little more beefy than a 400W PSU for a single card, but it's still inside the limit. As for Crossfire, 750W is absolutely plenty.
 
Zero82z said:
To answer both your questions, the CX400 can handle a modest system with a single 6950, and your 750W PSU can handle a pair of them without any issues whatsoever. I'd be more comfortable with something a little more beefy than a 400W PSU for a single card, but it's still inside the limit. As for Crossfire, 750W is absolutely plenty.
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Thank you! :) precise answer to both my questions. And that makes me happy to know my 750W wont have any issue with CF'ering x2 6950's.
 
I dont think so

right now my 550watt OCZ is I think close to the edge with my config. Having a 400 watt is playing with fire. you can burn yourself.
 
Zero82z said:
You're wrong on all counts.
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actually he is not that far off. his 6950 is unlocked and oced quite a bit so it probably pulls around 250 watts just by itself. throw in his oced cpu and rest of the components and he easily pulls 425 real(not at wall) watts while his psu only has 450 watts available on the 12v line.
 
cannondale06 said:
actually he is not that far off. his 6950 is unlocked and oced quite a bit so it probably pulls around 250 watts just by itself. throw in his oced cpu and rest of the components and he easily pulls 425 real(not at wall) watts while his psu only has 450 watts available on the 12v line.
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I'd put gaming load at around 300-350W.
 
NathanP2007 said:
Long story short, im building a PC, the PC for many months (up to 7) will have a 8600GTS GPU in it, however when the time arrives the PC will get a 6950 (or if they are out, a 7xxx series card). However, the PSU that will be used for the PC is a 400Watt one.

Specifically the CORSAIR CMPSU-400CX 400W ATX12V V2.2 80 PLUS Certified Compatible with Core i7 Power Supply

http://www.newegg.com/Product/Produ...9008&cm_re=CMPSU-400CX-_-17-139-008-_-Product
Click to expand...

Don't even think about doing that.It's not close to what you'll need in term of power.
 
Zero82z said:
I'd put gaming load at around 300-350W.
Click to expand...
he would easily hit 375-400 watts during many games. hardocp got 428 watts at the wall during BC 2 with stock 6970 so that right there is well over 350 watts. his is oced plus the Phenom 2 is very inefficient and when oced power goes way up.
 
hardocp got 497 watts at the wall just in BC 2 with an oveclocked 6970 so thats 425 real watts right there. http://hardocp.com/article/2011/03/14/asus_engtx580_eah6970_directcu_ii_review/9

and that is a wee bit lower clocked than velocityx has plus he has more drives. so indeed he is pushing his psu right to the edge with only 450 watts available on the 12v.

EDIT: oops that was for the gtx580. :eek:
 
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cannondale06 said:
hardocp got 497 watts at the wall just in BC 2 with an oveclocked 6970 so thats 425 real watts right there. http://hardocp.com/article/2011/03/14/asus_engtx580_eah6970_directcu_ii_review/9
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That was for the overclocked GTX 580. The overclocked 6970 was measured at 428W. Assuming that's accurate (it really isn't), it translates to a DC draw of about 350W. The test setup is also using an i7 920 overclocked to 3.6GHz, which has comparable power consumption to an overclocked Phenom II.
 
Zero82z said:
That was for the overclocked GTX 580. The overclocked 6970 was measured at 428W. Assuming that's accurate (it really isn't), it translates to a DC draw of about 350W. The test setup is also using an i7 920 overclocked to 3.6GHz, which has comparable power consumption to an overclocked Phenom II.
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my bad. 428 at the wall would still be over 370 watts though since that psu has 87% efficiency.
 
newbie question! so what happens if you dont have enough power? I am planning to do SLI or xfire too....
 
Zero82z said:
To answer both your questions, the CX400 can handle a modest system with a single 6950, and your 750W PSU can handle a pair of them without any issues whatsoever. I'd be more comfortable with something a little more beefy than a 400W PSU for a single card, but it's still inside the limit. As for Crossfire, 750W is absolutely plenty.
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How can you say a CX400 is OK for a 6950?
The AMD website says you need a 500W power supply: http://www.amd.com/us/products/desk...6950/Pages/amd-radeon-hd-6950-overview.aspx#3
And you need TWO 6 pin pci-e connectors, which the CX400 doesn't have, it only has one.
 
hoodisboi said:
newbie question! so what happens if you dont have enough power? I am planning to do SLI or xfire too....
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If you are lucky the power supply just shuts down. If you aren't, it could malfunction and die. If you are really unlucky it could kill other parts in your system. This is why you don't skimp on a power supply.
 
hoodisboi said:
newbie question! so what happens if you dont have enough power? I am planning to do SLI or xfire too....
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A good PSU will shut off. A bad PSU will burn out.
pgaster said:
How can you say a CX400 is OK for a 6950?
The AMD website says you need a 500W power supply: http://www.amd.com/us/products/desk...6950/Pages/amd-radeon-hd-6950-overview.aspx#3
And you need TWO 6 pin pci-e connectors, which the CX400 doesn't have, it only has one.
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Because I am basing my evaluation on the actual power consumption of the components that will be used, not on AMD's recommendation, which is overly conservative. 400W is enough. And yes, it's true that the CX400 only has one PCI-E connector, but that can be dealt with easily enough by using a molex to PCI-E adapter, which most video cards come with.
 
thanks cannondale for outlining all the data. on top of my gpu oc my phenom doesn't like my board or the other way around and I'm putting 1.45vcore (regular 1.35) to get that 3.4-3.5 overclock. it aint much but it makes a difference in games. I will be changing the cpu in the summer when zambezi comes out so it will be a new board a new cpu and probably a new PSU to be ready for a crossfire for christmas.

as for the 400watt supply, there are deals nowadays that can get you a 500-600 power supply really cheap. antec has good deals like that so I really don't see the reason why he absolutely has to stay at 400. just becaus its probably possible it's also probably running awfully close to the edge. and come on, if you got a card like that, you will one day get an itch to OC that baby and then the trouble start showing up.

so zero, I completely disagree with your recommendation for the psu.
 
OP here...i can settle this. First off, thank you Zero, i totally get what your saying. IMO i would bet that you are right. Not only is the system that would have used the 400W NOT a i7 OC'ed and all that stuff, but it was just going to be a simple E5200 Dual core with one HDD. I think 400W would have been enough.

However to settle everyone saying it wont work, or just buy a new PSU they are cheap. If you had read my first few posts you would have read that i remembered i have a PC P&C 610W that i can use for the E5200 build that will be getting a 6950 or 7xxx series card. Its in the family computer i bought but i can swap the 400W i got for the 610W in that PC.
So problem solved.

I just want to say thank you again Zero, though i say thanks to all for posting (like informing me it only has one PCI-E cable, wasnt aware). Yeah companies recommend stuff, and certain websites say it wont work, but like you said, you see their testing bed and you notice oh yeah..they used a OC'ed i7 with a $300 mobo with a few HDDs maybe even a SSD and etc etc etc. Well this build is barebones basic except the GPU.
And isnt the 6970 not really a good comparison to the 6950 because it uses more power? Hence the 6pin-8pin PCI-E plugs needed?
 
Zero82z said:
You're wrong on all counts.
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ehhh.... i think you shouldn't recommend something that close to the edge

a new 400W Corsair might cut it in the beginning, but

(a) they don't make 400w corsairs anymore... only the 430w which is inferior in 12V rail(lower amps) and manufacturer
(b) don't forget about capacitor aging. In a year, the PSU will be more stressed... can I come over and watch the fireworks? :D

well, OP's problem is solved anyways... just some info so that the next person who searches and reads his post doesn't crash his PSU
 
paperwastage said:
ehhh.... i think you shouldn't recommend something that close to the edge

a new 400W Corsair might cut it in the beginning, but

(a) they don't make 400w corsairs anymore... only the 430w which is inferior in 12V rail(lower amps) and manufacturer
(b) don't forget about capacitor aging. In a year, the PSU will be more stressed... can I come over and watch the fireworks? :D

well, OP's problem is solved anyways... just some info so that the next person who searches and reads his post doesn't crash his PSU
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Ehhh... I think you should reread my posts, because I never recommended getting a 400W PSU for this.

a) It doesn't matter if that model is still in production or not; the OP has one.
b) Capacitor aging is, for the most part, overblown nonsense.
 
Haha if my 400W crapped out cause of stress id be PISSED. That thing has been used as lightly as a republican senators wife. It was in my E5200/8800GT rig and was only on for 3 hours a day a few days a week and only to websurf, never once did i game on it or anything that would draw more power than idle.
Yeah, this thread will be confusing to someone with the same problem lol, overall id agree with zero that if its a high quality PSU, you can pull it off, but i wouldnt push your luck by OC'ing everything and using that PSU with that rig for years. But with how cheap PSU's are...theres not much reason to stick with a 400W, i saw my PC P&C 750W on Tigerdirect yesterday going for like $50!
Again thank you all. Im glad i found the 610W just cause now i can be 100% confident when building this PC and selling it to my friend.
 
Zero82z said:
Because I am basing my evaluation on the actual power consumption of the components that will be used, not on AMD's recommendation, which is overly conservative. 400W is enough. And yes, it's true that the CX400 only has one PCI-E connector, but that can be dealt with easily enough by using a molex to PCI-E adapter, which most video cards come with.
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Yeah, you are right, I get it now. I did a quick test with some parts I had here, and I didn't think it would work but it did. The results surprised me.

I have an old Sparkle ATX-400PA 400W power supply running a Phenom II X3 at 2.75 Ghz on a 785G MSI board. It only has 348W on the 12V rails total, and it's not 80+ efficient. It is several years old, and to be honest I got it from Goodwill for $7.
I was using the built in video for this machine and it was fine of course. I also recently got a GTX 260 core 216, but was planning on upgrading the power supply first before adding it.
Because of this thread I decided to try the card with the old 400W power supply, just to see if it would work. I did have to use one adapter because the power supply had only one pci-e 6 pin connector. I almost cringed hitting the power button the first time, but it started up just fine.
To load the GTX 260 I ran specviewperf 10, which I know is a professional app and doesn't make proper use of the gtx 260, but it's a long test and would probably stress the system pretty well. This benchmark took over an hour to run and I do also have a kill a watt, and it showed the system pulling around 250 watts or so. Of course I didn't watch it all the time since the test was so long.
I also ran the only game I have installed, which is Left 4 Dead, and played that a bit. It ran fine too. No issues there either. Of course I did notice that the exhaust from the power supply was much warmer than normal so that may reduce the life span, but I am not sure.
I did pull the GTX 260 out after this testing and will still probably get a beefier power supply just to play it safe for long term use, but a decent 400W power supply can do more than I thought.
 
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