2nd Graphics Card no video

[cooperhero]

Hello. I am trying to run 2 HD 5970's in crossfire. When I add the second one, the PC will turn on (LED's, fans running, etc) but there is no monitor, keyboard, or mouse output.
Bolth of the cards work independently, and work in bolth PCI-E slots.
I have enough power (900w)

CPU is E3-1245, but motherboard is a random Dell one (from t1600 workstation), so I am begining to think my motherboard is incompatable, but I also though crossfire deos not need motherboard support?

Running AMD Radeon Crimson 15.301.1901 Drivers and software (the newest software would not install, so I use this I had leftover from the last time I tried to get these to crossfire)

Also please don't suggest getting a new graphics card, I got these cheap and want to make them work, but if it is not possible it is not that much of a loss.

Thanks for any help you can.

Edit: sould say I am not using any other PCI-E lanes, only the ones for he graphics cards.

 

[sonnieharker]

the Dell t1600 uses a motherboard with C206 chipset, and im pretty sure this chipset doesn't supports multi gpu's, the other slot(s) are for wifi cards, sound cards, m.2 cards etc. sorry

 

[jaslion]

Hello. I am trying to run 2 HD 5970's in crossfire. When I add the second one, the PC will turn on (LED's, fans running, etc) but there is no monitor, keyboard, or mouse output.
Bolth of the cards work independently, and work in bolth PCI-E slots.
I have enough power (900w)

CPU is E3-1245, but motherboard is a random Dell one (from t1600 workstation), so I am begining to think my motherboard is incompatable, but I also though crossfire deos not need motherboard support?

Running AMD Radeon Crimson 15.301.1901 Drivers and software (the newest software would not install, so I use this I had leftover from the last time I tried to get these to crossfire)

Also please don't suggest getting a new graphics card, I got these cheap and want to make them work, but if it is not possible it is not that much of a loss.

Thanks for any help you can.

Edit: sould say I am not using any other PCI-E lanes, only the ones for he graphics cards.

Board doesn't officially even support dual gpu but dual gpu cards can work around this using 2 of them however is a no go.
Also why do you want to run 4 way crossfire no game supports that and barely any game in the past 2 years had support for 2 way crossfire/sli anyways.

Also don't forget that the hd 5870's these are made of are a 1gb variant and these are not enough for today's games even when running in crossifre a simple gtx 1050 will be a much better performer in every case compared to even quad 5870's (dual 5970's).

 

[COLGeek]

See the datasheet for the Precision T1600:

http://i.dell.com/sites/doccontent/shared-content/data-sheets/en/Documents/precision-t1600-spec-sheet.pdf

The issue is likely this "One or two PCI Express® x16 Gen 2 discrete graphics cards supporting 75W maximum combined power."

I don't see two HD5870s working in this rig. They pull too much power from the motherboard.