verification failure issues with GUIminer and amd 6990 running on single GPU

[tarui]

I am running a single amd 6990 and guiminer(2012-11-18)

Win 7 pro, catalyst 13.4. 6990 running on stock clocks.

I noticed my GUIminter output is only 350Mhash which means it's running on a single gpu. the Console also keeps telling me "verification failure...."

Gpu-z says crossfire is enabled but when i checked the temps/clock speed on each of the gpu, again it is obvious only a single gpu is hashing. Amd catalyst software also states the same thing.

Before posting this, I've tried uninstalling and running 11.4, uninstalling SDK and running version 2.4, 11.6, 11.8, 12.6,12.8, 12.10 and 13.4
except for 13.4, all of them gave me problems like CGminer/guiminer crashing upon startup or not detecting any GPUs.

on 13.4 CGminer always crashes after trying to login.

The best part, the hashing score is not showing on the pool's dashboard, so it's as if my amd card is mining for nothing.

I just noticed something. I am able to run CGminer with 2 tabs running at the same time, 0-0 and 0-1 (both with same username) but they have different hash rates, 350Mhash and 2.2mhash/s

[Yorzian]

Do you have a screen connected to your card ? The SDK sometimes cannot find a card if a screen is not connected to each card (I don't know about the 6990, but with a 7970 and a 7950 I need to put a dummy load on both so cgminer can really see them, otherwise it's like you, it shows up two cards but it's twice the same, hence the different hash rates).

[vm1990]

with a dual card in GUIminer you should be getting 3 devices in the device list
0-0 CPU
0-1 GPU core 1
0-2 GPU core 2

or somthing very similar so for what ever reason one of the gpu cores isnt showing up try installing the ATI/AMD drivers but dont do a restart and see if the both gpu cores show up in guiminer (close GUIminer then install the drivers)

also update your guiminer to the latest version
https://bitcointalk.org/?topic=3878.0

[vm1990]

Do you have a screen connected to your card ? The SDK sometimes cannot find a card if a screen is not connected to each card (I don't know about the 6990, but with a 7970 and a 7950 I need to put a dummy load on both so cgminer can really see them, otherwise it's like you, it shows up two cards but it's twice the same, hence the different hash rates).

it shouldnt be affected as its a dual card 2 gpus in 1 card so its in a constant crossfire config even when the crossfire is disabled

[Yorzian]

it shouldnt be affected as its a dual card 2 gpus in 1 card so its in a constant crossfire config even when the crossfire is disabled

Thanks for the details, I wrongly assumed that the dual card appears as two independant cards, not a crossfire set.