I have 4X7950+2X7990 = 8 GPUs on MSI Z77A GD55. Windows 8.1, Catalyst 14.4.
I installed the Catalyst without the Catalyst Control Centre. Then I used the Register modifier, there was no Code 43 in the device manager on any of the GPUs. However, 2-3 GPU would show 0 MHz in GPUZ. That means only 5 GPU is recognised and can mine.
Then I installed Catalyst with the control centre. I used the Register modifier, none of the GPU showed 0 MHz. They could all be used.
So, why no code 43 but showing 0 MHz?
I installed the Catalyst without the Catalyst Control Centre. Then I used the Register modifier, there was no Code 43 in the device manager on any of the GPUs. However, 2-3 GPU would show 0 MHz in GPUZ. That means only 5 GPU is recognised and can mine.
Then I installed Catalyst with the control centre. I used the Register modifier, none of the GPU showed 0 MHz. They could all be used.
So, why no code 43 but showing 0 MHz?
I've seen exactly the same issue on the same mobo.
It also had GPUs dissappearing time to time after reboots - this was solved by setting PCIe gen. to 1 in BIOS instead of auto.
Prly latency was also changed, but don't remember now..
And 0MHz was caused by driver enabling Crossfire if installed without Catalyst. Was solved by isntalling Catalyst and disabling Crossfire there. GPU-Z also showed something odd about Crossfire, I don't remember now, something like not-available, which is wrong, it should be Disabled(Available).
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