Hd 5970 and power supply

[Spike_xps720]

Dell XPS 720 H2C QX6800
Windows 7 Professional 64bit
Corsair Dominator DDR2 8GB SDRAM 1066MHz
GeForce 8800GT 500MB
1KW Power Supply
Samsung 305T 30 in. Monitor
Samsung SyncMaster 305T 30-inch LCD Monitor
Finally I purchased Gigabyte HD 5970 video card and I need your help one more time. Card has one 6-pin and one 8-pin plug. My power supply has only 6-pin connectors (I have 3 unused) and some 4 pin connectors. My question is how to connect those cables to 8 pin. Card was shipped with some molex adapters (one convert 2X 4-pin to 8-pin and other 2X 4-pin to 6-pin. Like I said before my power supply is ATX 2.0, EPS 12v I think Antec 1000W model.
What I did so far: I connected one 6-pin cable to card and using 2X 4-pin to 8-pin adapter connected to 8-pin in the card. Card work but when I start to play after one or two minutes computer shot down itself and I can turn it on without problems but shout down again without any messages. I tried different games but with same result.
I think the power connection is wrong or driver is corrupted. I had before Nvidia driver and I uninstalled it than after installation of driver from CD I downloaded 10.3 ATI Catalyst driver for windows7 64-bit. Maybe I should use driver sweeper Guru 3d (I saw this comment on internet).
Please help me one more time whit this problem. I hope you understand what I want to say.

 

[shadow187]

Try driversweeper, but that shouldn't effect anything.

Also, use the 2x 6-pin to 8-pin converter. Molex cables run off the +3 or +5v line IIRC, and those probably won't be too powerful.

 

[Spike_xps720]

I think you right, that is why HD 5970 working on easy tasks but shot down when is not enough power. So I ordered one Dual 6-Pin PCI Express to One 8-Pin PCI Express 2.0 Adapter Cable - Sleeved. I was confuse because conventor whitch I used now was included in the box with video card, why they gave mi it if it is useless?
http://www.overclock.net/power-supplies/676852-psu-gtx-280-6-pin-8-a.html
Thank you very much for info.
Chris

 

[Apotheosis]

Also with them antecs they usually have many low amp 12v rails, it should say some where on your power supply the amps of each of the +12v rails, you might have +12v1 28 amps +12v2 28 amps +12v3 20 amps +12v4 20 amps or something of that configuration, so when you plug things in you should try to figure out what plugs are on what rails and reserve 2 of the highest amperage rails for just your video card and plug all your other things into the other remaining rails.

If you do decided to buy another psu try to get one with a single +12v rail with high amperage. I have read reviews and they say they are the best to get.

I have a asus ati 5970 and i have it overclocked to 950 MHz core 1.2volts and 1150 MHz memory at 1.15volts and my psu is managing to handle this, I have a ultra x3 1000w and it has a single +12v rail at 70 amps. When I up volts on the core to 1.3 volts and overlcock to 1000MHz my psu starts to make a high pitch but low audiable noise and games arent stable and will eventually lock up computer so I think im at the limit of my psu. I monitor temps and they stay below the limits, cause im liquid cooling. But from what I read is the 6 pin + 8 pin + pci is only designed to handle up to 300watts of power, but I read you can get more then that if you have a psu with higher amps on a single rail. The stock speeds of the card reach max load of 294watts so ati already pretty much to the card to its limits. So im guessing im somewhere between 350w to 400w on my card.

 

[Spike_xps720]

So is this normal reaction when my Pc shut down when I am playing demanding games? I can play Age of Empires 3 for hours with 2560x1600 resolutions without crush but Crisis or Far Cry 2 no way.
Tomorrow I should get a dual 6-pin PCI express to one 8-pin PCI express 2.0 adapter cable and then I am going to connect all 3x 6-pin cables from my power supply is this will be enough to run HD5970 (I do not plan to over clock it)?

 

[shadow187]

Yes. The adapter to take 2x6-pin to 8-pin will provide the necessary power.

 

[Spike_xps720]

Best answer selected by Spike_xps720.