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Crossfire HD4870 - one card not appearing on device manager

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imported_dcp

Member
Hi guys,

I just moved from a SLI rig to Crossfire. I bought two HD4870, but for some reason the second card is not appearing on the device manager.

I can run either one by itself.

And then when I put both connected with the Crossfire cables (x2), I see the primary one, but the secondary isn't appearing.

My motherboard is Asus Maximus Formula (flashed with Rampage BIOS) - running E8400 at stock speed.

Could this be because my PSU isn't powerful enough to drive both? I have an OCZ PowerStream 600w. I know I must be right on the edge, but I see the second card powering up (i.e. the fan is running and the LED comes on).

Or is there anything (e.g. switch on the card?) that I missed? Besides one card not being recognized by the OS, everything else runs fine.

Any help you can provide is much appreciated.
 
Yep... Intel x38. I tried to look under the BIOS setting to see if there is something to set (e.g. XFIRE Enable?), but I didn't see a thing like it.
 
Yep, I tried that, but it wouldn't have helped anyway :-(

According to Vista, my second PCI-E is empty. It doesn't even register.

When I put another PCI-E (nVidia) card in the second PCI-E slot, it works (as a solo card of course). So, I know the actual PCI-E socket works, but somehow the slave XFIRE card doesn't register.

Thanks.
 
Have you tried changing each of the two crossfire bridges? I'm not sure if a faulty bridge would prevent the system from recognising the second card, so perhaps someone with a greater understanding could comment.

Other users experiencing similar problems report success when they drop back to the 8.10 drivers, but again, I have no idea.

Sorry I couldn't be of any help.


 
Supposedly, only one XFIRE cable is needed for the HD4870 (can anyone confirm or deny it?).

I used 2, and swapped the position with the same results. So, it really requires one, the swap would have let me know if one was fault.

Thanks all for help. This is just bizarre and driving me nuts 🙂 Of course, the AMD site isn't very helpful, and the manual from ASUS is pityful.

 
Originally posted by: VirtualLarry
pretty sure crossfire requires two cables, not one
Click to expand...

Not according to the AMD forum.

It says:

I know sapphire recommends you use only 1 on the 3/4xxx series for dual GPU set-ups as 2 can cause problems, but I have never seen any hard data supporting this but have recently run into trouble with two.
 
Originally posted by: FalseChristian
This may seem simplistic but make sure the cards are in firmly in the PCI-e slots.
Click to expand...

Yeah that's too simplistic ;-) I re-sat the cards so many times and can safely eliminate this possibility.
 
have you tried a fresh install of the OS and drivers?

I remember that when I first added the second 3870 to my rig back in 2007 I had a lot of trouble trying to get crossfire to runI would get the add new hardware prompt but it would always fail to detect the second card and just kept listing a unknown device.

I gave up stuffing around with the drivers and just reformatted and reinstalled my vista x64 and no I've had no problems ever since.
 
Originally posted by: Stumps
have you tried a fresh install of the OS and drivers?

I remember that when I first added the second 3870 to my rig back in 2007 I had a lot of trouble trying to get crossfire to runI would get the add new hardware prompt but it would always fail to detect the second card and just kept listing a unknown device.

I gave up stuffing around with the drivers and just reformatted and reinstalled my vista x64 and no I've had no problems ever since.
Click to expand...

Yep, done that as well 🙂 I reinstalled Vista x64 and x86 about 3 times each with no luck yet. I am about to give up... Xfire makes SLI look so much easier in comparison.

At this point, I wouild be happy to see the second card as an unknown device. At least I know it's getting detected 🙂 I am not even there yet.

 
Originally posted by: dcp

My motherboard is Asus Maximus Formula (flashed with Rampage BIOS) - running E8400 at stock speed.
Click to expand...

I ran the same rig for a while, sweet deal. I had ZERO compatability issues - it ran crossfired 4870's like a champ.

Originally posted by: dcp

Could this be because my PSU isn't powerful enough to drive both? I have an OCZ PowerStream 600w. I know I must be right on the edge, but I see the second card powering up (i.e. the fan is running and the LED comes on).
Click to expand...

Your PSU has adjustable rails, have you check to see if you are getting a red light?




 
Sounds to me like a mb issue. It'd be great if you could try a different one, maybe flashing the original Bios might help.
 
Originally posted by: Fox5
You're not supposed to use two crossfire cables with only 2 cards. Use only 1.
Click to expand...



Any links? I am not disagreeing with you, but I would like confirmation as I was under the impression that two cables are necessary and am using two cables.
 
Originally posted by: Red Irish
Originally posted by: Fox5
You're not supposed to use two crossfire cables with only 2 cards. Use only 1.
Click to expand...



Any links? I am not disagreeing with you, but I would like confirmation as I was under the impression that two cables are necessary and am using two cables.
Click to expand...

Sorry, no official confirmation, but I've heard of people having trouble with using 2 crossfire cables that were fixed by moving to just 1.
For what it's worth, I can confirm that using a single crossfire cable works just fine. I was under the impression that using 2 cables was meant for having 3 cards, but if you're not having trouble than I suppose it's fine, perhaps even correct.
 
Originally posted by: Fox5
Originally posted by: Red Irish
Originally posted by: Fox5
You're not supposed to use two crossfire cables with only 2 cards. Use only 1.
Click to expand...



Any links? I am not disagreeing with you, but I would like confirmation as I was under the impression that two cables are necessary and am using two cables.
Click to expand...

Sorry, no official confirmation, but I've heard of people having trouble with using 2 crossfire cables that were fixed by moving to just 1.
For what it's worth, I can confirm that using a single crossfire cable works just fine. I was under the impression that using 2 cables was meant for having 3 cards, but if you're not having trouble than I suppose it's fine, perhaps even correct.
Click to expand...

There's the thing, as a result of this thread I checked out my own CCC. Crossfire is enabled; however, as is the case with the OP, the Device Manager also tells me that I have only one card (2 x hd 4850's). It's something that I never checked given that the crossfire enable function came up as soon as I installed the second card. So, is crossfire enabled when the box is checked, even though Device Manager only detects a single card? I'm currently on 9.2 drivers and the original bios that came with the p6t v2. I'm assuming that updating the drivers and bios will fix things. I'll let you all know. Any suggestions or comments would be much appreciated.

 
Originally posted by: sgrinavi

Your PSU has adjustable rails, have you check to see if you are getting a red light?
Click to expand...

Yes. They are all green. I even replaced the PSU with a Corsair TX850W just to make sure it wasn't my PSU. Another $170 down the drain! 🙂 I should've just picked up an HD4890 instead of dealing with this insane madness. It would've have been cheaper too.

 
Originally posted by: Red Irish

There's the thing, as a result of this thread I checked out my own CCC. Crossfire is enabled; however, as is the case with the OP, the Device Manager also tells me that I have only one card (2 x hd 4850's). It's something that I never checked given that the crossfire enable function came up as soon as I installed the second card. So, is crossfire enabled when the box is checked, even though Device Manager only detects a single card? I'm currently on 9.2 drivers and the original bios that came with the p6t v2. I'm assuming that updating the drivers and bios will fix things. I'll let you all know. Any suggestions or comments would be much appreciated.
Click to expand...

That's interesting 🙂 Please let us know what you find out.
 
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