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Yet another - which PSU do you recommend? .. :P

Joshatdot

Joshatdot

Member
I am looking to replace my current system, and build a new one. I've decided on the i5-2500/k, and prolly 4x4GB of DDR3-1600 memory, maybe 2x8GB. An HD 6870, 120/128GB SSD SATA III drive, 1TB or bigger SATA .. etc misc other gubbins.

According to various PSU calcs .. what I come up with is a combined rating of 28.8A/346W of the +12v rail .. and total wattage of 427W. I know that PSUs are most efficient at around 50% load. I am thinking I should at the very least get a 650W or 700W, and optimal would be 800W (maybe 850W).

What do you think? I am not planning to SLI/XFire my system at all .. but possible upgrade the GFX down the road.
 
PSU calcs already greatly overestimate what you need. If you aren't OCing, your system is going to pull like 200-250 watts max. Get a nice 500 or 550 watter.
 
XFX 550W will have you covered for any single GPU upgrade later on. In a realistic load scenario, a system with 2500K OC'd + 6870 will use around 250-300W. The most powerful single GPU's will increase that by 100W, for which XFX550W is big enough.
I know that PSUs are most efficient at around 50% load.
Click to expand...
That doesn't mean it's economical to pay extra for a bigger PSU.
and prolly 4x4GB of DDR3-1600 memory, maybe 2x8GB
Click to expand...
Just checking - do you actually know for a fact that you need that much ram?
 
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lehtv said:
XFX 550W will have you covered for any single GPU upgrade later on. In a realistic load scenario, a system with 2500K OC'd + 6870 will use around 250-300W. The most powerful single GPU's will increase that by 100W, for which XFX550W is big enough.
That doesn't mean it's economical to pay extra for a bigger PSU.
Just checking - do you actually know for a fact that you need that much ram?
Click to expand...
:thumbsup:

I'm running its bigger bro XFX 650W but igot that because it was only +10$ where i live.
 
TemjinGold said:
PSU calcs already greatly overestimate what you need. If you aren't OCing, your system is going to pull like 200-250 watts max. Get a nice 500 or 550 watter.
Click to expand...

The i5-2500k & 6870 alone will pull 250W @ stock .. and I don't plan on OC'ing.

lehtv said:
In a realistic load scenario, a system with 2500K OC'd + 6870 will use around 250-300W. The most powerful single GPU's will increase that by 100W, for which XFX550W is big enough.

That doesn't mean it's economical to pay extra for a bigger PSU.

Just checking - do you actually know for a fact that you need that much ram?
Click to expand...

HD 6870 TDP is 150W & GTX 590 TDP is 365W .. slightly more than 100W :sneaky: .. and surprisingly the TDP is the same for Core i5s & i7s.

I'd rather be OP than 'this should be enough'.

4x4GB ram for $100 .. why not :awe:
 
Hypothetically if I got the most powerful i7 Sandy (still only 95W TDP) and the GTX 590, their combined TDP is 460W .. with the XFX 550W that doesn't leave much for POST draw and running power for the rest of the system.

Anywho .. I'd feel comfortable with a minimum of 600W from a decent PSU .. or a 700W if I decide I want a more 00ber GFX later on.

What do you think of these?
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139023
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139024
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021
 
Joshatdot said:
HD 6870 TDP is 150W & GTX 590 TDP is 365W .. slightly more than 100W :sneaky: .. and surprisingly the TDP is the same for Core i5s & i7s.
Click to expand...
GTX590 is not a single GPU, it's two GPU's on one card. If you want to be covered for dual-GPU cards or SLI/Crossfire setups, you'll want between 650W and 850W. However I'd recommend buying a 550W unit, and upgrading it in the unlikely event you ever go dual-GPU.

4x4GB ram for $100 .. why not :awe:
Click to expand...
What do you need it for? If you can't answer that, you don't need it - better spend the cash elsewhere. If you're just a gamer, 8GB is more than you will need in a looong time.
 
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Joshatdot said:
The i5-2500k & 6870 alone will pull 250W @ stock .. and I don't plan on OC'ing.



HD 6870 TDP is 150W & GTX 590 TDP is 365W .. slightly more than 100W :sneaky: .. and surprisingly the TDP is the same for Core i5s & i7s.

I'd rather be OP than 'this should be enough'.

4x4GB ram for $100 .. why not :awe:
Click to expand...

The i5 and the 6870 ALONE and AT STOCK will NOT pull 250w. Not even close. Don't believe what those calcs say. See my system? I sometimes touch 250 and NEVER cross 300 watts (my PSU measures draw from the wall; these numbers are actual power PSU supplied) while gaming or doing anything else and I (a) do NOT have a 6870 and (b) am most definitely NOT at stock.

But you know what, let's say you are right and those two do. The rest of the system is like 50 watts tops. What are you doing with an optimal 850-watter? I hope you know the difference between 50% load and 80% load is a few pennies a year electric cost-wise. The difference in price between quality 600 and 800 watt units is more than you can recoup in a lifetime of energy savings.
 
Joshatdot said:
Hypothetically if I got the most powerful i7 Sandy (still only 95W TDP) and the GTX 590, their combined TDP is 460W .. with the XFX 550W that doesn't leave much for POST draw and running power for the rest of the system.

Anywho .. I'd feel comfortable with a minimum of 600W from a decent PSU .. or a 700W if I decide I want a more 00ber GFX later on.

What do you think of these?
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139023
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139024
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021
Click to expand...

The two bottom ones are fine. I wouldn't do the two top ones.
 
I think realistically you won't need much more than a 500W, I mean a good quality 500W that is. But just to be on the safe side and in case future stuff need more juice, I'd get a nice 600-650W.
 
650W might be good if you were getting high-end power hogs and overclocking (which you're not, the i5-2500k and 6870 both have very reasonable power consumption), and anything higher than that would be good for SLI/CFX (which you're not doing).

Yup, 500W-ish is more than enough for just an i5-2500K and 6870. You can do some overclocking and still have some headroom leftover.
 
Thanks all .. I guess spec sheets, TDP and what not are not reliable to go by :hmm:. I'll pick out a nice, decent 550W ~ 600W then.

On a related question ..

How do PSU manufactures calculate their wattage/amperage rating? Take for example the Corsair TX650

+3.3V@25A, +5V@25A, +12V@53A

3.3V * 25A = 82.5W
5V * 25A = 125W
12V * 53A = 636W
--------------
Total 843.5W

I know if any PSU ran near their MAX .. they would fry and die, or shut off before. Is the 650W rating a average sustained?
 
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IGemini said:
My total power consumption while gaming barely hits 350W from the wall, and that includes the monitor chewing through 80W by itself (which is NOT taxed by the PSU)! Don't bother with TDP values. I'd go for this:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151094
Click to expand...

Newegg has 15% certain SeaSonic PSUs now until 2/8 so you might want to look at these as well:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151093
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151096
 
Ok...man, I've been refining my searches for hours it seems. Of these what do you recommend. They are 550w~650w, modular, 2x 6+2 PCIe, active PFC:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817703036
http://www.newegg.com/Product/Product.aspx?Item=N82E16817171036
http://www.newegg.com/Product/Product.aspx?Item=N82E16817341050
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139032

I am leaning toward the PC Power & Cooling PPCMK3S600 .. for $70 (after MIR) I think it's best. It seems very well reviewed at Hardware Secrets
 
Joshatdot said:
How do PSU manufactures calculate their wattage/amperage rating? Take for example the Corsair TX650

+3.3V@25A, +5V@25A, +12V@53A

3.3V * 25A = 82.5W
5V * 25A = 125W
12V * 53A = 636W
--------------
Total 843.5W

I know if any PSU ran near their MAX .. they would fry and die, or shut off before. Is the 650W rating a average sustained?
Click to expand...

Corsair TX650 is a decent power supply, and by that I mean that it can provide its labeled 650W of power continuously and safely. It may not be advisable though just to be on the safe side. You'd probably decrease the power supply's lifetime quite a bit if you ran it at 650W for hours every day.

What you listed there are the amperage ratings for the different rails. You're not supposed to add them up and say "this is the total safe power output of the whole PSU". It doesn't work like that. As I understand it: 25A on the 3.3V only means that you can draw a current of 25A on that rail before protections kick in, regardless of how much current is drawn from the other rails. It doesn't mean 25A is a safe continuous current on the 3.3V rail.

In addition to this over current protection (OCP) on each rail, you have over power protection (OPP) operating more or less on the whole power supply. When the total power draw exceeds a set limit, this protection will kick in - irrespective of what the current is in each rail. In good quality units, OPP tends to be set well beyond the labeled wattage. In other words good units are capable of momentarily providing more power than advertised, making the labeled wattage technically safe for long term use, provided none of the rails are overloaded.
 
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