Problem with AsRock X58 & four GPU's

Hi,

Does anyone have a clue about this problem:
I tried to put four gpu's (2 x 8800gt & 2 x 9800gt) to AsRock X58 Supercomputer mobo. System didn't boot at all, no signal from any gpu. It works fine with three GPU's with slot combinations 1,2,3 and 1,2,4. I have latest bios (1.4).

I don't need SLI, just eight outputs. Don't ask me why

I'm using Xilence 800w PSU.

+3,3V +5V +12V (1-4) -12V +5VSB
28,0A 32,0A 18,0A 0,5A 3,0A

As I wrote, booting with 3 is working fine. I'm just wondering that it doesn't do anything when I try to boot with four. Can't get even to bios, just a black screen.

Anyway, I already ordered Chieftec CFT-1200G-DF. Is it any good?

Should I get some of these instead:
Corsair HX1000W
ZALMAN ZM1000-HP
Cm Real Power Modular 1000W-E
OCZ PROSTREAM 1000W
Xilence 1000W REDWING

Thank you for recommendation. I will consider Corsair.

This rig is definitely not for just eight screens. Even 9800gt's are bit underpowered for this use, but I need to use one slot models and can't go for water cooling. It's a embedded product that will be first seen on 1st of april in Frankfurt. So, if you happen to be there it's free beer for the advice (in case it works)

4 9800GTs do not require a 1000W PSU. They use <=100W apiece.

A good quality 750W such as Corsair TX750 is a good choice.

I have to agree with that

Dunno what happened to ATI.. you cant even get a decent video playback without messing with Xorg.conf

The quality of the PSU is as important as the amount of power available. How many total amps/watts are available on the 12V rails (should be on the label)?

Yes, but an 800W PSU cannot actually have 72A (or 864W) available on the 12V. PSU labels will usually list the total available for the 12V.

If you get it working, make sure and post where it will be on display.
Guessing it is going to be attached to one of the stages for the musik fest
Don't worry though, I would not hold you to the free beer

I spent a good deal of time looking for official 4-way SLI power requirements or similar issues.
Unfortunately, I was unable to locate anyone with the same issue or any official power requirements.

The best logical argument I have is still for a underpowered PSU.

Your PSU:
660w/12v = 55a combine on the +12v

Each 8800gt/9800gt has a TDP of approximately 110w:
(4*110w)/12v = 36.66a

All current Intel Core i7 CPUs have a TDP of 130w:
130w/12v = 10.833a

The x58 chipset alone has a TDP of just over 24w:
24w/12v = 2a

Just your four GPUs, chipset and your CPU have a TDP of 49.5a leaving only 5.5a available.
This does not even account for the power draw of your motherboard, cooling fans, hard drives, RAM or the add in cards taking up the rest of your slots.
Even assuming the the highly unlikely possibility that you are still within your 55a envelope, many lower quality PSUs are incapable of delivering their rated power.
It is quite possible that your system is tripping your PSUs over volt protection when trying to run all 4 GPUs.

Anyways, that is the best explanation I can come up with for you.
I can not be 100% sure the PSU is the primary issue but, in any case, it should be upgraded.
Best luck getting it running, it may be interesting to see what you are doing with it

I know, but it is the maximum the part is rated to draw.
This just shows that, when the system is fully loaded, it is entirely possible that his PSU is not up to the task.
This is especially true if his is a low end unit.
Unfortunately, as I was unable to locate any valid reviews which points me towards it being a low end unit.
As I already stated, it may not be his primary problem, but it should still be upgraded.

Problem solved! (Kind of..)

For some weird reason this XFX combination of two 8800gt's and two 9800gt's is cursed. They all are perfectly working and no matter which order you put them in they don't work. I have combination of 9800, 8800 and two 9600gt's and it works. Weird ha?

I now ordered four PNY's 9800gt's. Let's see how it kicks.