Will my older PSU still suffice ?

mvm

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Dec 13, 2011
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Hi,

I would like to upgrade my system, with the following things
CPU: Intel Core i5-2500K
Graphics: AMD Radeon HD 6850 -
RAM: 2x 4GB DDR3
HD: Crucial m4 SSD 64GB, 2.5", SATA 6Gb/s + portable 2TB USB 3.0 HDD.
Mainboard: Gigabyte GA Z68
maybe a tv-tuner later

I still have an Enermax Liberty 400 W at home - will that supply enough power and have the right connectors for the planned system?

If not - what kind of PSU would you recommend (I would like it as quiet as possible). What if I want to put a second graphics card in there and overclock the cpu later ?

thank you for your help
mVm
 

AdrianPerry

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Cooler Master PSU's other than their Silent Pro range and high end models, are generally avoided.

Suggested PSU manufacturers include; Antec, XFX, SeaSonic, Corsair.

For an ATI 6850 a 450w PSU is recommended. A good 400w unit from the above manufacturers should be sufficient. The ENERMAX 400w unit you already have should be fine for a single card set up like what you have listed....

.....If that doesn't suffice:
Corsair do a nice cheap 430w builder series PSU that should be perfect for that system.
$34 after rebate and JonnyGuru recommended http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026

for a Crossfire set up, using x2 6850's - 650w PSU is recommended. Again look for the recommended brands (Antec, XFX, SeaSonic, Corsair) and look for an 80PLUS rating. Modular might be recommended, but by no means "required".
 

xtreme5

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well, 6850 eat up alone 430w what about the other component if he want to overclock then.
 

AdrianPerry

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I'm not sure where your getting that info from, but I'm almost certain its inaccurate....

See below:

Our test system is based on a power hungry Core i7 965 / X58 based. This setup is overclocked to 3.75 GHz. Next to that we have energy saving functions disabled for this motherboard and processor (to ensure consistent benchmark results). On average we are using roughly 50 to 100 Watts more than a standard PC due to higher CPU clock settings, water-cooling, additional cold cathode lights etc.

Keep that in mind. Our normal system power consumption is higher than your average system.

Measured power consumption - 6850

Advertised TDP = 127W
System in IDLE = 176W
System Wattage with GPU in FULL Stress = 278W
Difference (GPU load) = 102 W
Add average IDLE wattage ~ 19W
Subjective obtained GPU power consumption = ~ 121 Watts

http://www.guru3d.com/article/radeon-hd-6850-6870-review/10

Even with the GPU at full stress, its never drawing more than 278w from the wall.
 

AdrianPerry

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Did you read the above article or post at all?

It quite clearly states that the test system they use is VERY POWER HUNGRY with an over-clocked CPU, Water-cooling and cathode lighting.

So no matter how much more power you wanted to throw at the build by simply over-clocking the graphics card, a GOOD QUALITY 430w PSU is still going to provide plenty of headroom.

TOMs hardware recently made a build with SLI GTX 580's (which are recommended a 900-1000w PSU) and had it running on an 800w SeaSonic unit with no issues. Just shows what a good quality PSU can do.
 

Dark007

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If you want to be conservative, assume modern graphics cards consume 300W. That's high, I know -- they're more likely 230W for high end cards or 180W for mid-level modern cards. Then, CPUs have a thermal defect of ~60-100W, so assume its a little higher electrical consumption. HDDs, SDDs, RAM, Mobo, not much, but none the less, it should show you that 400W will not be enough. Don't forget -- capacitors lose capacitance over time too, especially if the system is left on 24/7. Assume ~2%/year loss on your PSU. With a reduction of capacitance, you can no longer support your maximum power draw smoothly, resulting in a potential interrupted power supply to your system.
 

AdrianPerry

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Also remember that in no situations will your PC be running 100% power load on every single component.....a 6850 has a recommended PSU of 450w.....a 430w Corsair unit with 80PLUS rating is plenty to power it. As i showed in my previous post, the entire system only drew 278w of power with the GPU in FULL stress....

If you really want to be safe, just go ahead and slam a 1000w unit in there. That will certainly see you through any "capacitor ageing".
 

mvm

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The PSU is roughly 3.5 years old, so I do not expect it to be super damaged by now - the computer was on at most 4-5 hours a day on average.
To me this all sounds like even my 400 W running at 70% of its advertised capacity should handle the 278 watts that AdrianPerry described - now the question is:

Could anything be damaged if the PSU turns out to be not strong enough? Or do I just shut down the PC and order a bigger one if it turns out I run into problems? (btw. what kinds of problems are we talking? Freezing of picture, total picture loss ... or more intricate stuff?)

thanks for all your replies

mVm

P.S.: I will not overclock with the 400 W PSU - I plan on maybe overclocking and adding a second Graphics Card for Crossfire somewhere down the road, which is why I buy the 2500K. But then I will definitely need another PSU anyhow.
 

mvm

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I understand that a new PSU is probably better than the old one. I am just asking if the old one is enough, and whether it might be dangerous to use with the other new hardware.
At some point in the future I will need a bigger PSU, I just rather not have that point be now.
 


 

mvm

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Thank you, that was what I was taking from the discussion, I just wanted to know about the general dangers of having a PSU that is too small - could I permanently damage any hardware by using the 400W one, if it turns out it is not powerful enough for some reason ?
 

diellur

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Enermax are a commendable PSU manufacturer, so you have a good unit. The age of it is a concern...if it wasn't sufficient, you'd soon start seeing issues like the PC hanging or resetting, artifacts on the screen etc. An old, quality PSU is different from a generic PSU, in that the quality PSU meets certain standards. I doubt it would kill components in your system.

A newer 450 - 500W PSU would be an idea...put it this way, you're buying new kit. Do you really want to risk that on not replacing a PSU? The odds are you'll be OK, but why play the odds?
 

mvm

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My main reason for considering keeping the small one is of course monetary - a new PSU of acceptable quality and output will probably be around 80 - 90 € around here, which I could save on other parts, but don't really want to - at the moment that would probably mean not getting the SSD.
The other main point, is that I know that the unit I have is silent. I have sent back a few PSU's when I picked this one because I couldn't stand the noise - this one I hardly notice when putting my ear next to its fan.
 

diellur

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Do yourself a favour...IMHO, the best option is to update the PSU. SSDs are getting cheaper and cheaper, and you have a Z68 mobo. Get your upgrade sorted out, including a new PSU, and pick up an SSD in a few months. Then, when you're enjoying the speed of your system, you have the peace of mind knowing that the components have a nice stable PSU supplying them.
 

mvm

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Dec 13, 2011
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Hi Everyone,

Just to let you know, the system is now up and running as
described in the first post. I used the 400W PSU and there
were no complications whatsoever.

Regards,
mVm