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Crossfire

bootboy

bootboy

bootboy

Associate
Joined
4 Mar 2006
Posts
12
Hi,

The basic's of my system are a Sapphire A9RD580ADV, Sapphire X1900XT Crossfire Edition, Sapphire X1900XT, AMD X2 3800, Akasa Power Plus 650w psu, 2x1 gig Crucial pc3200, Viewsonic VX924

I have just installed my second x1900xt card into my system and now windows xp wont boot, the system crashes as soon as the windows logo screen appears.
The croosfire edition is fitted into the correct slot, both cards will work correctly in either slot as long as the other card is not in a slot even if no power is connected.
All the mother board power connectors are fitted, the cards run off of seperate pcie connectors.

Is there a setting in the bios that I have missed to enable both pci slots to work together? or is it simply my power supply?
Any help would be much appreciated.

Thanks.
 
My BIOS has the option to enable the crossfire support. I also need to install em into the right slots. You tried that?

That PSU might be pushing it a little though. Shouldn't be but it might.
 
Hi,

Yep, the cards are in the correct place, they are clearly marked on the board.
I cant seem to find anything in the bios to enable crossfire and the the manual is about as much use as !!!!
I bought the psu because of the great reviews it as but it seams the 12 volt rail might not be adequate for this set up.
Any thoughts?
 
Well looking at the PSU that OcUK sell under the same name, it says its crossfire compatiable so I should think its ok.

What are the amps on each of the 12V rails? I think X1900's need/want 18A. Not sure though.
 
http://www.akasa.co.uk/akasa_english/spec_page/psu/spec_ak_p650ff_bkv1.htm

Its the same one, Akasa Ultra Quiet 650W PowerPlus Active PFC ATX2.0 PSU.
I have had a reply from one of the guys at sapphire's forums}

None of the 12v rails of that PSU are capable of running those cards together properly, and i'm surprised that it managed to power one with no issues. There's a PSU Section in the TOP STICKY thread read that ... you'll be needing a unit with a MINIMUM RATED (CONTINUOUS ) 12v rail of 35+A for optimal X-Fire performance with no power related issues.

So it looks like its the psu, Its just a bit frustrating that its brand new, comes recommended, but its not up to the job.
So I'm thinking FSP Sparkle FX700-GLN, any thoughts on this before I waste some more cash?

Cheers.
 
Global_Inferno said:
Im finding this a little confusing... how can that possibly not have enough power..?
Click to expand...
Its the most powerful, consumer available single core GFX card available, thats how :p (Or something like that)



I've got the 700W FSP GLN. Tis wonderful :D I didn't pay for it but its a lovely PSU. Looking at those ratings on the akasa, I agree with the sapphire guy. Suprised it ran with just one!

The FSP has 4 12V rails with 18A EACH. That should sort you out for a while.

Its got 8 SATA, 6 molex, 2 FDC and 3 PCI-E. That should keep you going for a while.
 
I dont quite understand myself, I have only 2 x sataII drives fitted, 2 x dvd writers, the case is a antec lanboy with 2 x 120mm fans, thats the total contents of my rig.
The psu as more sata conectors,pcie conectors and molex conectors than you can shake a stick at.
 
The FSP? Its not the connectors that are important, its the ratings on the 12V rail(s).

I'm pretty sure that on ATI's site they recommend 36A+ for running X1900's crossfire. Your akasa can only provide enough amps for ONE X1900 as only one of its 12V rails has 18A on it :)
 
I have a spare Jeantech 450w with a 22amp 12v rail, can I power this seperatly outside the case and just connect the slave card to this to prove the psu theory?
Is there any implications of using a seperate psu just to power a graphics card?
 
Well you can do that except you'd have to short two of the PSU ATX pins together to get it to turn on :p

Yea that'd work wonderfully :) Think of it, 450W and 36A just for ONE card. Should be fine.

Tis a good idea. I wouldn't of thought of that.
 
Its the green and any black, for future reference.
It stiil dont work, the cards suck power from the molex connected to the motherboard and thier own 6 pin conectors so i've tried power to the motherboard just off of the other supply and power just to 1 card off of the other supply but neither method works.
 
Yep, I tried all different assortment of connections but none seem to work, Its a shame because that would have proven the psu theory.
 
The description on OcUK doesn't actually say x1900 crossfire, so that could mean x800's, which it would power, still could be added into the description though that it wont power the top end crossfire, as im sure you'll not be the only one buying that PSU to power em. :)
 
Last edited:
Hi,

OK guys I have purchased an ATI X1900 crossfire certified psu, FSP fx700-GLN and I still have the same problem.
Any ideas?

Cheers.
 
Well I have that PSU and as your GFX cards work fine on their own I would suggest it was a problem with the motherboard/BIOS setting.

Have you stress tested both cards to make sure they're ok? I.e. 3Dmark06.
 
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