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Topic: SOLVED - Two 6990s different results. (1BTC Reward) - page 2. (Read 2108 times)

newbie
Activity: 12
Merit: 0
6990 will not work if memory clock is 100mhz below core clock, it will freeze instead.

These two 6990's are on separate motherboards, basically two different computers.
newbie
Activity: 42
Merit: 0
Is the first 6990 your primary display card and/or is it installed above the second physically?
newbie
Activity: 42
Merit: 0
Hey mezzan. I was having the same problem as well with my two 5830s. Personally, I've been using Sapphire TRIXX and I can crank out about 300 M/hash from both. I would suggest downloading it. Once you've installed it, before overclocking anything, click on the setting option. Uncheck Synchronize cards in Multi-GPU configs (I'm assuming you're mining with both cards via a dummy plug). Head over to the overclocking tab and change your settings to 945-975 Core Clock and 300-325 Memory Clock. Unless you want to go over 1000 Core clock, I suggest leaving the Voltage on stock.

After you've overclocked the first one, click on the down arrow. This will allow you to overclock your other video cards to the same settings. Make sure to press apply for each video card you over clock. You can save profiles so you don't have to always do it manually.

The fans will automatically adjust whenever you increase the Core Clock. If you'd like, you can set the fans to 75-90% by click on the fixed box under "Fan Control".

Click on info and double check to see if the clocks are showing he correct numbers.

HAPPY MINING!! Feel free to PM me if you have any questions!
newbie
Activity: 12
Merit: 0
Ah yes: -v -w128 -f1
sr. member
Activity: 280
Merit: 250
Interesting 400MH/s on that second card.
My Visiontek 6990 only gets 340-370~ MH/s on both cores. The second core likes to be a little lower usually.

Are you running any flags?
newbie
Activity: 12
Merit: 0
https://i.imgur.com/K46jy.jpg

https://i.imgur.com/UiEn1.jpg

It's kinda funny the difference between these two is about 100Mhash/s which is significant. I've been testing with different core and mem clocks for the first 6990 but still similar results.

INFO:
- Fan speed at 60% for both cards.
- FLAGS: -v -w128 -f1 (poclbm)
- Brand is PowerColor.
- First card uses 750W PSU, second uses 650W PSU.

Any ideas what went wrong? Or is it just the card?

Solution:
Set BIOS switch at "overclocked" position 1
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