11-02-2013, 05:05 AM
I figured out the 4G decoding early on when I got the "not enough PCI resources" error. I spent a good deal of time poking around the bios and adjusting things, but it was good to know I was on the right track.
I was able to track down my original issue, which was power related, but not in the way I was thinking.
My problem turned out to be the table on page 152 of the manual. It outlines the ports on the power distribution board that should be connected to each GPU. For example, it states J3 or J4 should be connected to GPU 8. Since the 7990's require two 4-pin connectors, I was connecting both J3 and J4 to the 7990. Instead, I should have connected either J3 or J4, and then chosen a port from the other channel on the PDB. Once I started alternating the ports (J3 with J5, J7 and J9, etc), everything worked fine. I can now run all four 7990's under the standard Ubuntu 12.04 setup.
Which brings me to the cooling problem. While the Tyan does indeed push a biblical amount of air, two of the GPUs heat up to 90c in about 3-4 minutes and oclHahscat kills the run. The rest stay about 5-10c cooler, but they all climb into the 80's before the run is killed. I set the auto fan control in the bios to off so the case fans stay on full blast, but that doesn't seem to help. The 7990's idle in the mid 40c range. I used amdconfig to set the GPU fan to 100 percent as well, but that only helped delay the temperature cut-off another minute or so. The cards are spaced out a slot from each other and from the sides, so there is plenty of room for air to move around them. It looks like you are using the factory case fans from the pictures you posted as well. Is there anything else you had to do to keep the 7990's in the mid 70's?
I was able to track down my original issue, which was power related, but not in the way I was thinking.
My problem turned out to be the table on page 152 of the manual. It outlines the ports on the power distribution board that should be connected to each GPU. For example, it states J3 or J4 should be connected to GPU 8. Since the 7990's require two 4-pin connectors, I was connecting both J3 and J4 to the 7990. Instead, I should have connected either J3 or J4, and then chosen a port from the other channel on the PDB. Once I started alternating the ports (J3 with J5, J7 and J9, etc), everything worked fine. I can now run all four 7990's under the standard Ubuntu 12.04 setup.
Which brings me to the cooling problem. While the Tyan does indeed push a biblical amount of air, two of the GPUs heat up to 90c in about 3-4 minutes and oclHahscat kills the run. The rest stay about 5-10c cooler, but they all climb into the 80's before the run is killed. I set the auto fan control in the bios to off so the case fans stay on full blast, but that doesn't seem to help. The 7990's idle in the mid 40c range. I used amdconfig to set the GPU fan to 100 percent as well, but that only helped delay the temperature cut-off another minute or so. The cards are spaced out a slot from each other and from the sides, so there is plenty of room for air to move around them. It looks like you are using the factory case fans from the pictures you posted as well. Is there anything else you had to do to keep the 7990's in the mid 70's?