PSU - How much do i need?

[teradoom]

Hello,

So im thinking of putting together a 2x Hd6850 GPu with either i5 2500k or the i7 26(7)00k with a Asus P8Z68-V LX.

I checked new egg and they recomend 600w PSU but others say a lot more. So how much do i need if i was to have all the 16gb 1600rams and a ssd plus HDD fans etc the whole lot?

 

[ram1009]

I could buy a 850W psu, but what would be the point when my PC only pulls 300W from the wall at 100% load? There is the law of diminishing returns to consider as well.

I agree about diminishing returns but your example is unrealistic. Nobody builds a 300W machine today so it would be nearly impossible to achieve the nearly 3/1 ratio you suggest. Personally, I try to never let my rigs exceed 50% but when trying to get out some quick advice I often say to get the biggest quality PSU that the OP can afford. That way they're not encumbered with a bunch of intimidating calculations and it's preferable to err on the high side than the low side.

 

[sk1939]

Actually, the machine in my signature only pull 300W from the wall at 100% load (thanks to F@H). Tour right in the sense that if you have multiple graphics cards, and optical drives and such, your power requirement goes up, and it is indeed easier to buy a larger one than a smaller one, so long as they don't go nuts and buy a 1500W PSU for an i3.

 

[ram1009]

Actually, the machine in my signature only pull 300W from the wall at 100% load (thanks to F@H). Tour right in the sense that if you have multiple graphics cards, and optical drives and such, your power requirement goes up, and it is indeed easier to buy a larger one than a smaller one, so long as they don't go nuts and buy a 1500W PSU for an i3.

I agree completely. I hope I didn't convey anything else. I usually suggest buying the biggest quality PSU they can afford. I believe that limits nearly everybody to parameters we both agree on. Someone buying a 1500W PSU is surely looking for bragging rights anyway.

 

[teradoom]

Best answer selected by Teradoom.