If your monitor connected to the 7990? Try setting the display output to iGPU in the motherboard BIOS.
When I used the onboard as the primary I'm unable to modify clocks on the card. 
Topic: PowerColor 7990 Halp! (Read 714 times)
If your monitor connected to the 7990? Try setting the display output to iGPU in the motherboard BIOS.
The GPU commands make no difference, for some reason it'll just only run at 97% on both cores while at 13 intensity.
For me, on scrypt, only Intensity of 13 works. Two threads always runs poorly or crashes. Thread intensity doesn't make much difference. Core: 1049, Mem: 1500 are the best OC settings I could get, it's around 1080-1088 kh/s at these clocks.
However, I've discovered that SHA-3 Keccak runs great! Hardware errors around 12-13, but it doesn't drop hashrate much to lower it. Intensity around 9-10 gives around 700-710 mh/s, Core: 1200, Mem: 1100
Now if only more coins were based on Keccak.
(only ones I know are Helixcoin, Maxcoin, and Copperlark)
For me, on scrypt, only Intensity of 13 works. Two threads always runs poorly or crashes. Thread intensity doesn't make much difference. Core: 1049, Mem: 1500 are the best OC settings I could get, it's around 1080-1088 kh/s at these clocks.
However, I've discovered that SHA-3 Keccak runs great! Hardware errors around 12-13, but it doesn't drop hashrate much to lower it. Intensity around 9-10 gives around 700-710 mh/s, Core: 1200, Mem: 1100
Now if only more coins were based on Keccak.
(only ones I know are Helixcoin, Maxcoin, and Copperlark)
Have you added setx GPU_MAX_ALLOC_PERCENT 100? That would be your first step, you can either do so in a separate console window, or add it as the first line of your batch file, ie
"set x GPU_MAX_ALLOC_PERCENT 100
cgminer.exe -o soso.com....."
I personally open a command prompt, run the command "set x GPU_MAX_ALLOC_PERCENT 100" then it should say value accepted. Close the command prompt. Open your batch, and try for higher TC values. See what your hash is like with a high TC, -g 1, and higher intensity. According to the list, some of the cards prefer single thread, high TC, high I, and some prefer two threads, lower TC and intensity.
I should add, I do not yet have a 7990 (just ordered one 5 min ago, in the process of searching for info I found your thread, so I want to discuss with you so I have a head start on getting mine configured before it arrives)
I do however have a 7950 which requires similar tweaking so I have some experience with these 79xx.
What is your ASIC Quality in GPU-z?
For now I would say reset back to stock GPU/mem, let's find your best hash rate there, whether it is -g 2 low TC, or -g1 high TC, and then work on your OCs. I have found that works best. Overclocking first can lead you to sometimes have what appears to be stable OC, but crashes or HW errors when you crank the intensity. At stock speed we can get a good read on whether your card is a -g 2 or -g 1
"set x GPU_MAX_ALLOC_PERCENT 100
cgminer.exe -o soso.com....."
I personally open a command prompt, run the command "set x GPU_MAX_ALLOC_PERCENT 100" then it should say value accepted. Close the command prompt. Open your batch, and try for higher TC values. See what your hash is like with a high TC, -g 1, and higher intensity. According to the list, some of the cards prefer single thread, high TC, high I, and some prefer two threads, lower TC and intensity.
I should add, I do not yet have a 7990 (just ordered one 5 min ago, in the process of searching for info I found your thread, so I want to discuss with you so I have a head start on getting mine configured before it arrives)
I do however have a 7950 which requires similar tweaking so I have some experience with these 79xx.
What is your ASIC Quality in GPU-z?
For now I would say reset back to stock GPU/mem, let's find your best hash rate there, whether it is -g 2 low TC, or -g1 high TC, and then work on your OCs. I have found that works best. Overclocking first can lead you to sometimes have what appears to be stable OC, but crashes or HW errors when you crank the intensity. At stock speed we can get a good read on whether your card is a -g 2 or -g 1
I have a PowerColor AX7990 Radeon HD 7990 (not the devil edition, but it appears to have clocks unlocked already). I've read of people getting over 1200 KH/s on the same exact card, but I'm unable to get more than 1088 KH/s out of it with the perfect OC'ing settings (after hours of work).
Using the latest Radeon drivers and SDK.
Coreclock: 1049, Memclock: 1500
Intensity set to 13, it won't run at good speeds on anything else.
Most people have posted -g 2 for 7990, but I get severely lower speeds with it.
Thread concurrency 8192, and Could be set higher but I'm not sure that it helps any.
No other settings being changed from default seemed to help.
Is this card a lemon?
Using the latest Radeon drivers and SDK.
Coreclock: 1049, Memclock: 1500
Intensity set to 13, it won't run at good speeds on anything else.
Most people have posted -g 2 for 7990, but I get severely lower speeds with it.
Thread concurrency 8192, and Could be set higher but I'm not sure that it helps any.
No other settings being changed from default seemed to help.
Is this card a lemon?
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