SLI and Crossfire kicking the crap out of PSU's

**chunkylover77** · 03-02-2006, 03:55 PM

Seems as if some of the SLI certified power supplies are not quite up to par.
http://www.extremetech.com/article2/...1932947,00.asp

**Dumo** · 03-02-2006, 04:01 PM

Enermax 660W death in combat here.....with 1900CF and FX60 overclocked

**dinos22** · 03-02-2006, 04:02 PM

INQ reported recently that they need single rail PSUs for X1900 Xfire rather than multi rail PSUs

**nn_step** · 03-02-2006, 04:13 PM

Originally Posted by Dumo

Enermax 660W death in combat here.....with 1900CF and FX60 overclocked

Jebus dude that has to suck.. atleast none of the parts got hurt right?
because that is what matters...

**Elfear** · 03-02-2006, 04:25 PM

Interesting. Looks like the problem occurs from load balancing the system. The gpu's draw too much power through one of the 12V lines and the overvoltage control kick in and shuts things off.

So do you guys think the new 700W monster from FSP would be perfect for this scenario. Here is a quote from Xbit's recent review of the psu:

"The declared characteristics are truly impressive. The FX700-GLN has four +12V lines with a current of 15A each, and the only limitation to their combined load is the overall wattage of the unit, i.e. 680W for the main rails. In other words, the manufacturer promises you can load this power supply through one 12V power rail only."

I take that to mean that any one 12V rail can be loaded far above the rated 15A. Not sure what that comes out to as I don't think it would be additive like 15Ax4 = 60A. Maybe someone with more knowledge of this stuff can chime in.

**dinos22** · 03-02-2006, 04:41 PM

you guys would be better off sticking to one of the PSUs from the review or get a nice 650+W PSU with a good single 12v rail......i mean i you can afford X1900 xfire might as well do that

**Kunaak** · 03-02-2006, 05:00 PM

Athena Makes a 850 watt PSU, with I think 48 amps on a single 12 volt rail.
thats the PSU I been eyein for the last month now. it's $280 at newegg.

**chunkylover77** · 03-02-2006, 05:00 PM

The only problem I have is that I cant stand noise. So the PCP&C models are out. I am hoping their new Silencer models coming in April/May are going to be SLI ready.

**situman** · 03-02-2006, 05:46 PM

Originally Posted by Dumo

Enermax 660W death in combat here.....with 1900CF and FX60 overclocked

The Liberty 620 passed all tests.

**nn_step** · 03-02-2006, 05:53 PM

Originally Posted by situman

The Liberty 620 passed all tests.

Doesn't really matter.. heck I once overloaded a PCP&C 1kw..
It happens..

**situman** · 03-02-2006, 05:59 PM

What the heck were u powering? A space telescope?

**nn_step** · 03-02-2006, 06:01 PM

Originally Posted by situman

What the heck were u powering? A space telescope?

try about 50 15k SCSI drives in Raid0

**Lando95** · 03-02-2006, 06:15 PM

Originally Posted by nn_step

try about 50 15k SCSI drives in Raid0

LMAO! That'll do it. Happen to run HD Tach while you were at it?

I have seen several guys running 500-550 watt single rail psu's on GTX's in SLI with no problems. How much wattage does an oc'ed high end video card consume at full load?

That FSP 700 that Elfear mentioned sounds like it might do the trick, if the load balancing works like they say it should.

**nn_step** · 03-02-2006, 06:24 PM

Originally Posted by Lando95

LMAO! That'll do it. Happen to run HD Tach while you were at it?

I have seen several guys running 500-550 watt single rail psu's on GTX's in SLI with no problems. How much wattage does an oc'ed high end video card consume at full load?

That FSP 700 that Elfear mentioned sounds like it might do the trick, if the load balancing works like they say it should.

crapped out midway through..
but the Graphics cards pull out 120W stock and up to 180+w when overclocked with voltmods..

**Shadowmage** · 03-02-2006, 08:40 PM

200W/12V is 17A....

2x cards should saturate the 12V pretty well in most ~500W PSUs.

**dinos22** · 03-02-2006, 09:01 PM

Originally Posted by Shadowmage

200W/12V is 17A....

2x cards should saturate the 12V pretty well in most ~500W PSUs.

how to you work that out again

**ugp** · 03-02-2006, 09:05 PM

The FSP does work well...I haven't had any issues at all yet...although I am not running CrossFire yet...but the PSU is indeed very nice and very solid. It was an excellent choice people here helped me with...

**alpha0ne** · 03-02-2006, 09:13 PM

My Tagen (see sig) has a switch that combines the 12V rails into one rail, I wonder if that would help in an SLI situation (not that I will ever use SLI) or maybe help with high OC's when my dual core is sucking ~ 200Watts

**Xenogias** · 03-02-2006, 09:33 PM

my question is how do you know what rail you are drawing from? My OCZ 600w has all the plugs marked for different devices, sata, vga, p4, etc but from what i am reading you dont really know in most cases which 12v rails you are connecting to your devices...someone correct me if im wrong. i couldnt find anything about this in the manual.

nn_step:
I didnt think you could do RAID 0 with anything near that many drives. What controllers/hacks were you using? And isnt that way overkill for scsi320?

**GMX** · 03-02-2006, 10:22 PM

Originally Posted by Xenogias

my question is how do you know what rail you are drawing from? My OCZ 600w has all the plugs marked for different devices, sata, vga, p4, etc but from what i am reading you dont really know in most cases which 12v rails you are connecting to your devices...someone correct me if im wrong. i couldnt find anything about this in the manual.

nn_step:
I didnt think you could do RAID 0 with anything near that many drives. What controllers/hacks were you using? And isnt that way overkill for scsi320?

nn_step post's are full lies and utter exaggerations. It's become standard accross the board to just ignore his "post jockey" property.

**Dumo** · 03-02-2006, 10:38 PM

Originally Posted by GMX

nn_step post's are full lies and utter exaggerations. It's become standard accross the board to just ignore his "post jockey" property.

Thats not nice

This is an important thread, hopefully we can pinpoint any problems before a lot of psu goes tilt.

**biohead** · 03-02-2006, 10:46 PM

Originally Posted by GMX

nn_step post's are full lies and utter exaggerations. It's become standard accross the board to just ignore his "post jockey" property.

Just because you know everything best, right

**Dumo** · 03-02-2006, 10:53 PM

Lets go back to topic

So.... single 12V psu is better to run SLI/CF?

**Lando95** · 03-02-2006, 11:17 PM

Originally Posted by Dumo

Lets go back to topic

So.... single 12V psu is better to run SLI/CF?

That seems to be the case, but we won't know until someone tests a multi-rail psu that can run full amperage on 1 12V rail.

**Cooper** · 03-03-2006, 12:30 AM

Originally Posted by Dumo

Lets go back to topic

So.... single 12V psu is better to run SLI/CF?

IMO it`s just depends on actual model and it`s schematics. As macci sad he had problems running CF with OCZ600 which has two 12V rails and no problems with single 12V rail PSU. But in this thread good example about using FSP 700GLN with 4 12V rails on CF/SLI system. And despite all those brands there are only several actually different schematics in PSUs. And under few brands logos there just might be same one PSU.

P.S. nn_step HDs don`t use 12V rail

they use 3.3&5.

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