What wattage do I need?

[TheHornyDonut]

So I'm getting a new PC here's the specs:
Intel i7 4770k (which will be OC'd to 4.5GHz~)
16GB Corsair Dominator Platinum (2 cards)
Dual SLI GTX 770 SC
2x 120gb RAID0 OCz Agility SSD's
750GB WD Green
3TB WD Green
Asus Sabertooth z87 Motherboard
Corsair H100i
And probably around 4-6 120mm fans.

I've been on various PSU Calculators and have been given different results. Some have told me that I will need about 1100w and others at about 650w.
Can anyone tell me which one I should go for? Because I've been looking at Corsair AX860i and the 1200i. Just need to know which one I should get.

 

[Warrgarbl]

I would probably choose something with more than 800W to factor in the alleged capacity loss that PSUs are said to have over their lifetime. I am not sure if this is actually relevant, and even more so when using a high spec PSU such as the Corsair AX series, but I like to be sure.

The 860i should be totally fine. The 650W seem about right to me, although a full stress test load - which is not indicative of real life loads - could go as high as 700-750W.

 

[Jameson Clark]

I would have to suggest you go closer to 850W and definitely wouldn't go 650W

 

[Someone Somewhere]

Yeah, 850W for 770 SLI. You should be OK with a 750W, but OCing will add extra power draw.

I wouldn't bother with any i-series PSUs. It's a complete waste of money and they aren't calibrated, so you get as accurate a result by guessing. I had a friend who's 860i said it was running at 99% efficiency, which is pretty unlikely.

On another note, don't bother with the Dominator RAM, and run a mile from Agility SSDs. Don't bother with RAID, either.

I generally consider Sabertooths to be a waste of money, too.

 

[avjguy2362]

This has more to do with thermal efficiency and power consumption. IF your finances allow it, a bigger power supply will always use less power at the wall and run cooler than a smaller one. All things being equal, if your system needed 550 watts, a 1200 watt PS would use less power at the wall and run cooler than a 650 watt unit. A Corsair AX860i is an outstanding PS and will likely be more than good enough, but if I were gaming all the time ( frequently using high power ) I would go with the bigger PS! Big PS's are an excellent long term purchase that will last you many builds over 7+ years. Hard to say that about anything else except possibly a case!

 

[Someone Somewhere]

bigger power supply will always use less power at the wall

Wrong. In fact, running a power supply down at the ~20% efficiency will use more power than a smaller PSU running at ~50%, assuming both fit the same efficiency curve

run cooler than a smaller one

That at least is usually correct.

But overbuying is just a waste of money. Spend it elsewhere. Get a better SSD - go for a decent 256GB one, or even 512GB.

 

[TheHornyDonut]

Yeah, 850W for 770 SLI. You should be OK with a 750W, but OCing will add extra power draw.

I wouldn't bother with any i-series PSUs. It's a complete waste of money and they aren't calibrated, so you get as accurate a result by guessing. I had a friend who's 860i said it was running at 99% efficiency, which is pretty unlikely.

On another note, don't bother with the Dominator RAM, and run a mile from Agility SSDs. Don't bother with RAID, either.

I generally consider Sabertooths to be a waste of money, too.

I already have the SSDs, taking them out of this PC. And I know the problems with Agility, been there, fixed that.
Also, I like the extra performance I get from RAID0.
I know it's not exactly a safe or efficient RAID array to use, but I prefer the faster boot up speeds. 1GB/s is awesome!

 

[TheHornyDonut]

I would probably choose something with more than 800W to factor in the alleged capacity loss that PSUs are said to have over their lifetime. I am not sure if this is actually relevant, and even more so when using a high spec PSU such as the Corsair AX series, but I like to be sure.

The 860i should be totally fine. The 650W seem about right to me, although a full stress test load - which is not indicative of real life loads - could go as high as 700-750W.

Yeah, that's what I was thinking. Just kinda' confused me a bit when I was getting mixed results from different calculators.