Power supply for hd 6950 in crossfire?

shea1980 · 7 Feb 2011 at 12:56

Hi guys i am going to buy another hd 6950 and put them in crossfire,what Watt of a PSU would be adequate?thanks

RJC · 7 Feb 2011 at 13:01

650W onwards will be plenty

Ezyryder · 7 Feb 2011 at 13:13

650W onwards ... but it has to be a quality unit.

shea1980 · 7 Feb 2011 at 13:32

thanks guys

Skellig · 7 Feb 2011 at 13:47

700w just for that breathing space (especially with o/ced CPUs)

hdpcgamer · 9 Feb 2011 at 06:03

Would a Corsair HX650 be able to comfortably handle a heavily OC'd quad CPU & OC'd 6950's in crossfire bearing in mind that the PSU is suppose to be able to supply a maximum of around 720/740 watts?

Skellig · 9 Feb 2011 at 07:49

hdpcgamer said:
Would a Corsair HX650 be able to comfortably handle a heavily OC'd quad CPU & OC'd 6950's in crossfire bearing in mind that the PSU is suppose to be able to supply a maximum of around 720/740 watts?

A HX650 will definitely by fine. But why not something cheaper with more power?

Cooler Master Silent Pro Modular 700W

Or Antec 750w Modular at other sites?

hdpcgamer · 9 Feb 2011 at 15:51

Skellig said:
A HX650 will definitely by fine. But why not something cheaper with more power?

Cooler Master Silent Pro Modular 700W

Or Antec 750w Modular at other sites?

I already own a HX650 so was wondering if I choose to go quad cpu/dual-6950, I wouldn't need to change my PSU.

C64 · 9 Feb 2011 at 15:57

The hx650 has more power as far as I know the hx650 is 52 A 12v and the one you linked is 50 A 12v.

MikeHiow · 9 Feb 2011 at 16:31

They pull around 150w each at 100% load in Furmark. 650w will be plenty.

Skellig · 9 Feb 2011 at 18:56

C64 said:
The hx650 has more power as far as I know the hx650 is 52 A 12v and the one you linked is 50 A 12v.

Meh, a 6950 CF set up won't really demand more than 48A 12v.

And the Antec TruePower 750 will last a v. long time. Four +12V output to deliver up to 62A combined load. I'd definitely go for Antec 750 if I was looking for a long lasting PSU.

hdpcgamer · 9 Feb 2011 at 19:41

MikeHiow said:
They pull around 150w each at 100% load in Furmark. 650w will be plenty.

Cheers, I'll guess I can keep hold of my HX650 if I choose to go with 2x 6950's.

blackninja · 9 Feb 2011 at 21:56

To give you an idea ... I just ran mine with a meter at the wall socket (wall/PSU assuming 80% efficiency):

Idle at windows desktop 190/152
Running Heaven 2.1 max 569/456

That means GPUs under load = additional 379/303

my 6950s have unlocked shaders @ 940/1450 (1.2v gpu core)

Puppetmaster · 9 Feb 2011 at 22:36

Is that 569 with both?

MikeHiow · 9 Feb 2011 at 22:38

blackninja said:
To give you an idea ... I just ran mine with a meter at the wall socket (wall/PSU assuming 80% efficiency):

Idle at windows desktop 190/152
Running Heaven 2.1 max 569/456

That means GPUs under load = additional 379/303

my 6950s have unlocked shaders @ 940/1450 (1.2v gpu core)

This test is wrong.

You need to load the CPU with p95 or similar and take power figures with CPU at 100%, and then with CPU at 100% and GPU at 100%.

Heaven will be using the CPU, too, therefore that 303w increase is not just the graphics card.

Predicament · 10 Feb 2011 at 00:15

blackninja said:
my 6950s have unlocked shaders @ 940/1450 (1.2v gpu core)

Would such a setup destroy any game?

hdpcgamer · 10 Feb 2011 at 03:51

Predicament said:
Would such a setup destroy any game?

All except Metro 2033.

Predicament · 10 Feb 2011 at 11:10

hdpcgamer said:
All except Metro 2033.

really?

How graphically intense is it...

MikeHiow · 10 Feb 2011 at 11:34

It's pretty intensive, but my 6950 handles most of it just fine maxed out, with only a few evident slow downs in more complicates scenes.

hdpcgamer · 10 Feb 2011 at 16:44

Predicament said:
really?

How graphically intense is it...

It is definitely one of the most intense games out there - especially if running in DX11 and turning on depth-of-field which most people seem to disable anyway due killing the FPS to much without any apparent gain.

If you game at 1920x1080 then you may see framerates of around 45+ but so far I haven't come across a single benchmark where Metro 2033 is running at 60+ completely maxed out.