900W Dark Power Pro - Overclocking key.

[Penny]

Hi.

I'm running a 900W Be-Quiet Dark power pro. I have two 5970's running in crossfire from this PSU but it's very unstable.

I have been running the PSU in multi-rail (at least I think so) as I have two PCI-E power cables running from the PCI-E

Slots PCI-E 1 and PCI-E 2.

These run as follows

PCI-E 1 too the Top ATI 5970

and

PCI-E 2 too the Lower ATI 5970

I placed the Overclockswitch onto the PSU and switched it on and booted up again with BOTH PCI-E

Cables running too both the cards as above.

Is this now running as a single rail or do I need a Single PCI-E cable running from the PSU PCI-E 1 slot

with a splitter on it that feeds to both PCI-E cards at the same time?

The manual doesnt explain a thing and I don't know if my setup is correct. I hope someone with more knowledge

can help explain single and multi rail in laymans terms for me as I cant find any guides on the internet

to help me with my Be-Quiet PSU.

Does single rail mean that I only use one PCI-E cable to power both cards?

Hope someone can help.

Cheers.

 

[AMDFTW]

in what way is it unstabble

 

[Aurus_OC]

A power supply with a single rail design means that it is able to deliver its rated wattage through only one +12V rail. A multi rail design implies that the power supply has several +12V rails delivering the wattage to your parts. The key part with graphic cards is that they require a certain amperage on the +12V rail that the card's PCIe connector is plugged into. So you will need to locate the sticker on your PSU and tell us what the Ampage on the +12V rails are. If your power supply has a modular interface it the manual should tell you which connectors on the back are using which rail. However, that doesn't mean that every connector on the back is using a different rail.

It would be the easiest for us to tell you what's going wrong if you post a picture of the sticker on your power supply. Also like AMDTW said, in what way is it unstable?

 

[Penny]

A power supply with a single rail design means that it is able to deliver its rated wattage through only one +12V rail. A multi rail design implies that the power supply has several +12V rails delivering the wattage to your parts. The key part with graphic cards is that they require a certain amperage on the +12V rail that the card's PCIe connector is plugged into. So you will need to locate the sticker on your PSU and tell us what the Ampage on the +12V rails are. If your power supply has a modular interface it the manual should tell you which connectors on the back are using which rail. However, that doesn't mean that every connector on the back is using a different rail.

It would be the easiest for us to tell you what's going wrong if you post a picture of the sticker on your power supply. Also like AMDTW said, in what way is it unstable?

Here is some info that might help you guys help me out.

I'm running into issues with screen flicking on and off/Random crash to desktop im most game after about thirty mins of play time/Crash to blue screen/Some time the cards seem to be running at full power and then some times low FPS

everything in my system is brand new.

I just wondered if im running this PSU in overclocker mode now or do i need to get a single power cable that plugs into PCI-E 1 on the PSU and feeds both cards?

Thanks for the fast replies though guys.

 

[Penny]

I for got to add that the white connection in the bottom right hand side of the top picture is the Overclocker Key which I have plugged in and swithed on now with everything else connected as explained above.

 

[Penny]

Also I posted to this site as I read a review of the Be Quiet PSU Be Quiet Dark Power Pro P8 1000w Review Done by James Napier of this site. He did the review with this single rail Overclockers Key enabled but didnt go into detail on how to achieve this option as I'm fairly novis in my computer knowledge I need help making sure this option is enable so that I can test my system. If not I'm going to save for a better PSU and sell this one on ebay as I think it is the cause of the problems.

Mind you the ATI drivers to not help at all. They are terrible for the 5970 in SLI. Going Nvidia in six months and selling those aswell if they keep playin me up.

I have a friend who runs two 480's in SLI and hasn't had a problem with them, infact we had a LAN a few weeks back and it was embaressing how many times my rig

crashed.

 

[Aurus_OC]

First, thanks for the pics!

Have you tried it without the "overclocker key"? Are your cards overclocked? If yes it might be a bad overclock causing your troubles, so try it at stock.

I would be concerned about the amperage of your +12V rails , because 32A at the best is quite low for a 5970 card. I think it pulls somewhere from 20-25A at full load.

 

[Penny]

First, thanks for the pics!

Have you tried it without the "overclocker key"? Are your cards overclocked? If yes it might be a bad overclock causing your troubles, so try it at stock.

I would be concerned about the amperage of your +12V rails , because 32A at the best is quite low for a 5970 card. I think it pulls somewhere from 20-25A at full load.

No I do not overclock anything on my system it is all Standard SPEC. Yes I ran into major problems with and without this overclocking key.

I have only just connected this overclocking key again and comae on here to see if it's setup correctly so that I can test my games again?

If I was to get a new Single Rail PSU over crimbo what would you recommend as I'm fed up with these problems?

 

[Aurus_OC]

Get a Corsair TX, AX or HX series power supply. The last two are modular, but they are all great PSU's.

 

[equk]

I don't find this thread that helpful.

How is the psu unstable at the moment?

Also does the psu cope ok with 1 card installed?

The whole PSU rails debate and 'buy x' isn't exactly that helpful.

Jim is probably the best person to ask about PSU's but from reading the first post it just seems like the PSU is getting blamed for instability without any testing

It seems the overclocking key should combine all 12V rails into one so you get the full potential of the psu (like the corsair tx850).

A lot of PSU manufacturers will have multiple rails which combine due to the power usage of newer GPU's always seems to be increasing.

* Dedicated single +12V rail offers maximum compatibility with latest components

Source: OC3D Corsair TX850W Review

Just make sure you don't try switching the 'overclock key' with the PSU on

So on single rail it should be ok, if you still get problems maybe try with one card.

 

[lasher]

Hi Penny.

What drivers you running?

Please post full systems specs.

dont go running for a new PSU when it could be something simple!

Exhaust all possibilities first.

What temps is your system displaying when under load.

Use something like Afterburner to record them or http://www.cpuid.com/softwares/hwmonitor.html

Get back to us with these before spending your hard earned pennies or blaming the PSU.

 

[SimonW2011]

Hi

I believe running the graphics cards of of the modular psu ports for pcie cards 1 and 3 aka top and bottom with the oc key off will fix this problem, this was on the back page of my manual.

Thanks

Simon

 

[dugdiamond]

what mobo are you using, and does it have any extra 6-pin atx power supply sockets close to the PCI-E slots? if so, is it connected?

some boards need the extra oomph from this, as well as being directly supplied from the PSU