CF HD 7850 on a Rosewill Green 630w PSU?

[jordonc]

Is it possible (and safe for my components?) to crossfire two HD 7850s on a 630w psu? The AMD website suggests at least 600 watts. This is my first build that I just assembled a week or so ago: i5 3570k overclocked to 4.2, Rosewill Green series 630w psu, GA-Z77X-UD3H mobo, 8GB DDR3 Mushkin 1600, LG dvd/cd combo drive, 3 case fans, a hyper 212 evo w/ stock fan, a Spinpoint F3 1TB HDD, and 6 or so USB accessories. I've read quite a few comments about staying away from any psu not from Seasonic, Corsair, or Antec, but check out this review from hardware secrets on the Green series 630w:
Rosewill Green 630 Watt PSU
My current PSU has 50A on the 12V rail, and 2 available 6-pin PCI express power connectors.
I won't CF any time soon, and I probably won't even buy the first card for a few months. I just wanted some feedback to know if when I get the 2nd 7850, whether or not I'll need a new psu to go with it.

 

[dudewitbow]

edit reread nvm

edit2: technically its possible to xfire if you have 7850 at stock, but dont expect to overclock much, since the quality of the green series drops when it gets hotter

 

[buzznut]

Is it possible (and safe for my components?) to crossfire two HD 7850s on a 630w psu? The AMD website suggests at least 600 watts. This is my first build that I just assembled a week or so ago: i5 3570k overclocked to 4.2, Rosewill Green series 630w psu, GA-Z77X-UD3H mobo, 8GB DDR3 Mushkin 1600, LG dvd/cd combo drive, 3 case fans, a hyper 212 evo w/ stock fan, a Spinpoint F3 1TB HDD, and 6 or so USB accessories. I've read quite a few comments about staying away from any psu not from Seasonic, Corsair, or Antec, but check out this review from hardware secrets on the Green series 630w:
Rosewill Green 630 Watt PSU
My current PSU has 50A on the 12V rail, and 2 available 6-pin PCI express power connectors.
I won't CF any time soon, and I probably won't even buy the first card for a few months. I just wanted some feedback to know if when I get the 2nd 7850, whether or not I'll need a new psu to go with it.

You're overclocking, which the i5 is quite efficient but still for myself I would spring for 750W. The PSU will run most efficient at 50% load, so that's what I base my buying decisions on.

As far as the brand goes, I like to take each power supply on its own merits. If I'm buying a powerful PSU for a gaming rig, I like to see a 5 year warranty. I couldn't tell if this was the case from your link, but usually budget units come with a 3 year. You are doing the right thing, keep looking at reviews and weigh your options.

Go to Jonnyguru.com to read in depth reviews of power supplies.

 

[jordonc]

edit reread nvm

edit2: technically its possible to xfire if you have 7850 at stock, but dont expect to overclock much, since the quality of the green series drops when it gets hotter

I appreciate the input. Like I said, this is my first build, and while overclocking my CPU was a little stressful, I need to do homework on how overclocking works on graphics cards. But I've read in multiple posts that some models of the 7850 respond very well to overclocking. More than likely, I'll OC my first card, and then upgrade my psu for the second.

 

[dudewitbow]

I appreciate the input. Like I said, this is my first build, and while overclocking my CPU was a little stressful, I need to do homework on how overclocking works on graphics cards. But I've read in multiple posts that some models of the 7850 respond very well to overclocking. More than likely, I'll OC my first card, and then upgrade my psu for the second.

normal models usually have a 860 mhz speed. most people can overclock their 7850 to somewhere around 1050 mhz

 

[jordonc]

You're overclocking, which the i5 is quite efficient but still for myself I would spring for 750W. The PSU will run most efficient at 50% load, so that's what I base my buying decisions on.

As far as the brand goes, I like to take each power supply on its own merits. If I'm buying a powerful PSU for a gaming rig, I like to see a 5 year warranty. I couldn't tell if this was the case from your link, but usually budget units come with a 3 year. You are doing the right thing, keep looking at reviews and weigh your options.

Go to Jonnyguru.com to read in depth reviews of power supplies.

It's nice to hear from someone that reads individual reviews instead of saying that anything from "X" manufacturer for power supplies is complete garbage. I checked newegg, where I got all of my parts, and it only comes with a 2 year warranty. I have the feeling that a build like mine that has a pretty solid CPU, mobo, and eventually graphics cards deserves an equally solid psu. Sounds like I'll be upgrading my psu for sure when a single 7850 isn't cutting it anymore.

Edit: I went to jonnyguru and it just gave me a link to the exact same review that I put up in the first post. I thought you might get a kick out of that.

 

[ko888]

For a system using two reference clocked Radeon HD 7850 graphics cards in 2-way CrossFireX mode AMD specifies a minimum of an 600 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 32 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

For two factory overclocked cards, like the XFX Radeon HD 7850 Black Edition, I would increase the combined +12 Volt continuous current rating to at least 36 Amps.

The Rosewill Green Series 630W Continuous@40°C (RG630-S12), with its combined +12 Volt continuous current rating of 50 Amps and with one 6-pin and one (6+2)-pin PCI Express supplementary power connectors, is more than sufficient to power your system configuration with two Radeon HD 7850 in 2-way CrossFire mode.

So there's no need to buy a new power supply.

 

[jordonc]

normal models usually have a 860 mhz speed. most people can overclock their 7850 to somewhere around 1050 mhz

I just read a review for a new MSI 7850 overclocked to 1250mhz out of the box. MSI Radeon HD 7850 2GB Power Edition Overclocked Video Card Review But who knows when it'll be available and for how much.

 

[dudewitbow]

I just read a review for a new MSI 7850 overclocked to 1250mhz out of the box. MSI Radeon HD 7850 2GB Power Edition Overclocked Video Card Review But who knows when it'll be available and for how much.

1050 is just the safety limiter on the card, some models have to go through a roundabout way to get a clock past 1050

 

[jordonc]

For a system using two reference clocked Radeon HD 7850 graphics cards in 2-way CrossFireX mode AMD specifies a minimum of an 600 Watt or greater power supply. The power supply should also have a combined +12 Volt continuous current rating of 32 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

For two factory overclocked cards, like the XFX Radeon HD 7850 Black Edition, I would increase the combined +12 Volt continuous current rating to at least 36 Amps.

The Rosewill Green Series 630W Continuous@40°C (RG630-S12), with its combined +12 Volt continuous current rating of 50 Amps and with one 6-pin and one (6+2)-pin PCI Express supplementary power connectors, is more than sufficient to power your system configuration with two Radeon HD 7850 in 2-way CrossFire mode.

So there's no need to buy a new power supply.

You see, this is the answer I was hoping to hear from someone, that I was fine and there was no need to get a new psu if I wanted to xfire in the future. But now I've heard arguments for both sides. Life is full of decisions I suppose. I'll have to consider my budget when I get to that point also.

 

[jordonc]

1050 is just the safety limiter on the card, some models have to go through a roundabout way to get a clock past 1050

Ahh. I see. Well I'm still far from committing to a specific card, and who knows what new cards will come out and how prices will shift in the meantime.

 

[buzznut]

You see, this is the answer I was hoping to hear from someone, that I was fine and there was no need to get a new psu if I wanted to xfire in the future. But now I've heard arguments for both sides. Life is full of decisions I suppose. I'll have to consider my budget when I get to that point also.

I suppose buying a new PSU is optional, and I do know the 7850's are pretty efficient. Perhaps this will do until you have greater needs in the future. ko888's info looks solid, so you should be ok for now.

 

[jordonc]

Alright, well I appreciate everybody's input. I just wanted to wait a day or so to see if anybody had any additional thoughts. I probably won't be buying a new psu any time soon at least, maybe not for this build at all. But maybe I'll get a nice 750W that's modular as something to transfer to a new build when i need one. But I'll have to save up for my 7850s first. Thanks again.

 

[jordonc]

Best answer selected by jordonc.