Hi,
I have following parts:
- 4x Sapphire Radeon 6990
- 2x Antec 1200 Watt PSU's coupled together
- 4x 16x PCIe extender with power connected to the PSU directly.
- Windows 7 64-bit
- ATI 11.8 drivers
However, I can't get everything to work together. Up to 3 cards, everything works stable. When I add the 4th, the system almost always (99% of the time) doesn't boot and stops at BIOS error code 25h:
Early PCI initialization:
- Enumerate PCI bus number
- Assign memory & I/O resource
- Search for a valid VGA device & VGA BIOS, and put it into C000:0
From my testing it seems that there's something wrong with the first card even though it works perfect in a 2-way and 3-way setup. When the system powers up, the 3 other cards seem to start and spin up, while the first, even though it spins, doesn't make as much noise and doesn't generate as much 'wind'. I also have to move my monitor to the 2nd card or I don't get a picture...
Seems to me a Clear PSU Problem.
Are you sure the two power supplies Are correctly connected?
Meaning same Ground (that should be ok otherwyse you would not have a motherboard or other components by now. And maybe a lot of smoke ... )
And pin 14, the green wire for ATX power up and boot.
Seems to me the pin 14 is not correctly connected on Both ATX connectors.
Hence One of the PSU's that feeds the cards does not boot, does not deliver power.
The fact that the fans do not work properly almost proves the point.
By the way, Googling I found the same error 25 and somebody solved the exact same issue.
Regards.
