Power requirement for crossfired 5770s

  • Thread starter Sharky.
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Sharky.

Sharky.

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Per the title - I'm considering grabbing a second Radeon 5770 graphics card and crossfiring it with my existing card, but I'm not sure what the absolute minimum power requirement would be for such a setup.

My system runs a 600w Vantec ION2+ PSU - AMD's site lists 600w as the minimum for crossfiring the 5770s, but the 5770s don't use all that much power (something like 240w total calculated power for two), and http://extreme.outervision.com/PSUEngine comes up with 364w recommended for my system with two cards. I have an i5 750 with a mild OC to 3.04 (uses 80w), two 7200rpm SATA hard disks, a DVD+RW drive and one PCI card (WLAN) installed, so considering all that, would I be be able to comfortably power crossfired 5770s?

Azure?
 
I think you are in the safe, honeslty. I didn't look too much into the optimal amount to run dual 5770s, but I know I left a far amount of room when I picked up my 600Watt PSU this summer.

And it looks like you've done some extra research yourself, so I'd imagine it would be stable, provided you aren't trying to overclock everything or some silly nonsense.
 
Cheers 👍

Might as well give it a go - if it works it works, if it doesn't I can just leave one card unpowered until I get an 800 PSU or something :)
 
From the newegg website for AMD 5770/
450 Watt or greater power supply with one 75W 6-pin PCI Express power connectors recommended (600 Watt and two 6-pin connectors for ATI CrossFireX technology in dual mode)

Looks ok but I would have like to see higher amps on those rails. It has all the required connectors.

I'm running dual 4870's and they take a lot power but my PSU has one 12 V rail @ 56 A. Its also 750 watts.
 
I run crossfire 5770 with i5 750 on a 550W. No problems. They say 600 cause they assume you have a ****full PSU. But if you calculate the power draw its probably only around 350w for the whole system.
 
Yeah, calculated power was around 350w for my system, so my 600 should - on paper - be able to power it and then some.

I have ordered the card, so we shall find out soon enough!
 
Looking at that PSU, two 12V rails with 22A each is enough easy. And if it's not you'll just get instability, not the blow you and everything up that most people think happens if you try to run too much on a PSU..
 
Casio
And if it's not you'll just get instability
Click to expand...
Yeah, and in that case I'd just leave one card unpowered until I upgraded the PSU. Based on what I've read and calculated, I shouldn't have a problem - but you never know.
 

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