View Full Version :  SLI problems 2x7800GTX 512mb 

04-11-06, 03:30 AM
Hi all, Im very disgusting with my combo.
Im have very serious problems with SLI, here my config:
Opteron 170@2700 / Asus A8N32 de luxe / Raid 0 maxtor 2 HDD / DVD-ROM / DVD-RW/ 2x 7800GTX 512 XFX XXX / Creative X-Fi / psu: Hiper PS-XP-580 BF Modular SLI Certified.

When Im installing the first 7800 the system runs OK and the second 7800 plugged the system detected very well.
In the control panel of nvidia the SLI is correct and running 3dmark 06 very well but in the plug of pci-e there is a electrical noise.
Im tested FEAR,COD2.... and thats OK but when Im restarting the system windows lockup and BSOD. the Ez-plug in not connected because the motherboard have a 24 pin plugged and obviosly Im tried with the Ez-plug and the system hang on.
Its a Asus A8N32 a Bull***t ? my psu is good, in a few forums Im saw this psu with identical combo like me and running like a rock.

Im desesperate, the Nforce, forceware and bios are ok.

Thank you very much.

PD: Excuse my English its so poor.

04-11-06, 05:01 AM
It could still be your PSU, just because someone else's system is stable with it doesn't mean your PSU or any other component is ok.

Have you tried pushing each card seperatly? How about running the system with the bare needed components installed? What drivers are you using? Bios version? Your motherboard could also not like the ram...

04-11-06, 05:38 AM
All drivers and bios are the last one and the bios too.
The system have been running with all like a rock, the vgas are the same bios, and work properly without SLI.
:( The SLI running very well but when restarting the system......:( BSOD.


04-11-06, 07:35 AM
Have you tried a new OS install? A BSOD upon boot sounds like either a bad windows installation, bad HD or bad RAM. It could also be a PSU going bad but those usually cause resets not BSODs.

04-11-06, 10:43 AM
Yes Im tried the fresh OS install, this is the spec of my psu.

power: 580 W (up 630 W)
PFC Activo: yes
+3.3V: 32A
+5V : 36A
+12V 1: 20A
+12V 2: 18A
-12V : 0.8A
5Vsb: 2.5A
N4 Pines: 10
Standart Compatible: ATX 12V V2.2
Conector 24 pines: Si

04-11-06, 11:26 AM
It could be something as simple as a bad connector on the PSU or motherboard, all you can really rely on is process of elimination, test the likely culprits one piece at a time.

That electrical noise doesn't sound too promising, I would start by looking into that first.

The Bigman
04-11-06, 05:42 PM
Fist off check your spelling better please its not that good, and i think its a voltage problem with the card off the PS. I would test the PS with a volt meter and amp meter too to see whats the deal.

I have an ASUS A8N-32 Deluxe and works fine for me with my 550PS. and i run sli 7800GTX and 4 HD's no probs here.

04-11-06, 05:43 PM
the noise is out, bad plug:). But the SLI not work properly, Its maybe the psu but I doubt.
Pci-e from psu to 7800 and 2 molex adapter pci-e in exclusive rail to other one 7800....:(
any opinions?
Desesperate mode ON

Thank you for your replies.

04-11-06, 05:44 PM
He said it was not his first language,cut him some slack. ;)

04-11-06, 06:01 PM
He's asking for hardware help, cut the spelling nazi rubbish, if your that bothered by it become a teacher and educate folks.

I have a strong suspicion your PSU aint cut out for the job, I don't like this molex adapter business, time and time again I have seen SLI choke through using these.

04-11-06, 07:16 PM
I'm also leaning towards the PS being the problem. Do you know someone you can borrow one from to give it a try?

So it boots fine with just one card in. Have you tried swapping the cards locations? Or maybe switch which power connectors they are using...You've probably already tried that but you never know. Definately weird. Maybe try reinstalling windows?

04-12-06, 03:36 AM
Ok, thanks for the replies and excuse me for my English :o .
Im try the videocards separately and works perfect, Im suspect that the Psu is the problem but I dont have another one like this psu with similar watts.
Im looking for a new psu and send this one to rma.
Ive seen a few models but its complicated to choose one because Im so tired with this problem.
I dont want to think in another psu and the problem persists.
This is models that I see:

-Enermax EG701AX-VH(W)SFMA (2x PCIe, gold)
+3,3V 34 A
+5Vsb 2,5 A
+5V 34 A
+12V1 18 A
+12V2 18 A
+12V 35 A
-12V 0,8 A

-Enermax Liberty 620 vatios (2x PCIe)
+3,3V 28 A
+5Vsb 3 A
+5V 32 A
+12V1 22 A
+12V2 22 A
+12V 36 A
-12V 0,6 A

And this one is that I have in this moment and not work properly:

thanks a lot :)

04-19-06, 03:52 PM
I found the solution of my problems, In the bios of the motherboard, I change the config the Peg link.
A few days ago in the bios I put the config in "normal" and this config destroy the SLI stability.
I put in auto mode and run properly.


04-19-06, 06:11 PM
Congrats on finding the solution. They should get rid of the PEG link mode since it trips up lots of people like that.