New PSU for 6870 CF: 850 or 1k?

[Anubis]

Ill most likely be adding a 2nd 6870 soon and my current PSU wont work with that.

will a 850 cut it or will i need to go larger? Ill most likely be getting a Corsair HX series

Rest of the system is this

I7 920 @ 4 GHZ
6 GB ram
3-4 HHDs
2 optical
mobo/fans and such

 

[Rifter]

a quality 850w is fine.

Im running SLI 460's which use slightly more power with a i7@4.2Ghz off a corsair 850TX.

To be honest 750w would be more than enough.

 

[Compddd]

A quality 750W PSU like a Seasonic X-750 can run GTX 580 SLI just fine.

You don't need an 850W or 1000W for 6870 CF, save yourself some money.

 

[hardboy]

no 750w can run 580 sli. but for op's rig a good 850 will do

 

[theAnimal]

no 750w can run 580 sli. but for op's rig a good 850 will do

Any good quality 750W would have no problem with 580 SLI, unless you're doing major OC. Since 6870 uses less power, there is no need for 850.

 

[hardboy]

You are playing on the edge with 750 for 580 sli. And with oc up probably will kill something or there other soon

 

[BTRY B 529th FA BN]

A nice 950w model

 

[Bacstar]

I got dual 6870's crossfired, 6-HDD's, 1-SSD, Phenom II 965 @ 3.9ghz, optical disk, and 6-120mm fans running on an 850W powersupply. When everything is fired up and running full-bore, I'm using almost 550-600watts as reported by my UPS and 290watts @ idle.

Edit: i forgot I have my monitors plugged in the UPS, so may want to subtract 40-50watts from that.

 

[dma0991]

A 1kW PSU for a HD6870 CF is insane. If you are using a 850W true power PSU currently I suggest you keep using it. I've built a rig with HD6870 CF using a 700W PSU and it works fine. Even a 650W PSU is enough for a HD6870 CF.

 

[WaTaGuMp]

I would go for.


OVER 9000

 

[Rifter]

I would go for.


OVER 9000

Nuclear power FTW

 

[Anubis]

A 1kW PSU for a HD6870 CF is insane. If you are using a 850W true power PSU currently I suggest you keep using it. I've built a rig with HD6870 CF using a 700W PSU and it works fine. Even a 650W PSU is enough for a HD6870 CF.

When i made this post i was using a 550, went with a 850, slightly overkill but future proof

 

[Bacstar]

When i made this post i was using a 550, went with a 850, slightly overkill but future proof

Also, it allows the PS to run cooler and maybe more efficiently. I like the fact that I can keep adding stuff without worrying too much about overloading it. Another thing to remember, as PSs get older, their output decreases.

 

[theAnimal]

Also, it allows the PS to run cooler and maybe more efficiently.

If you run at very low load it will run much less efficiently.

 

[Skott]

A decent 750w (Corsair TX750w for example) will run 2x6950 fine so for 2x6870 you shouldn't have a problem. However if you plan on running something better than 2x6950 some day you may want to jump up to the 850w (Corsair HX850w for example) just to play it safe.

 

[Suspicious-Teach8788]

Get the Seasonic X750 or go Corsair AX-850.