LOL
ho formattato il pc installato windows 8.1 NON ho messo i driver e ora mi vede 6 gpu...
ridicolo...
Era scritto anche in uno dei post in inglese
https://litecointalk.org/index.php?topic=11761.30****** So I added the 6th card to my rig again, booted up and got the code 43 as expected. Im running windows 8 on a gigabyte 990fxa-ud3, with 5 radeon r9 290's and 1 r9 270x.
I installed windows 8.1, and at first boot into the desktop windows recognized all 6 cards as "basic video adapters" aka no drivers installed.
I installed the amd 13.12 drivers and rebooted and still got a code 43.
So as im re-reading this thread, I must have missed the IMPORTANT detail of "DO NOT USE ANY SPECIFIC DRIVERS" aka the official amd drivers. 
I will uninstall them tonight and try letting microsoft find the drivers themselves and hopefully that fixes it. ******
utilizza i driver di sistema, pero' non accenna alle prestazioni
leggi qui :
https://bitcointalk.org/index.php?topic=424437.0I think the 13.1 drivers where the last AMD drivers that allow more than 5 GPUs per rig, I used the 13.1 with 5x R7950s using a UD5 mainboard.
12.6 are the only driver from AMD that allow more than 5 GPUs, at least ~recent driver.
13.1 from AMD does not work for 6+GPUs.
13.1 from TechPowerup works for 6 x 6950/6970/7950/7970/280x cards.
13.12 W8.1 from Microsoft works(at least at the time of the post) for 6 x 290/290x, that's the driver Windows installs automatically.
13.12 mod v3 works for 7 x 290 confirmed on W8.1 so far.
OS: windows 8.1 , uninstall amd drivers then restart. use DDU to clean up registry keys then reboot. attach all GPU on the board, don't use dummy plug. once the exclamation sign is present on all 6 cards, install amd catalyst 13.1 from techpowerup, finally, install amd app sdk v2.8.
Certo che e' una gran bella seccatura
Speriamo che in AMD recepiscano il problema e lo risolvano
Ho trovato un mini-howto per chi e' alle prime armi con Linux , puo' essere magari un aiuto
To start :1. Install the Ubuntu
2. Update Ubuntu fully ( dal terminale : apt-get update apt-get upgrade )
3. Download the latest AMD Beta drivers for Linux, and download the fixed CGminer from
http://www.ohmpie.com/mining-on-an-r9-290-in-linux/ Do not download anything else.
4. Extract the AMD drivers to your home directory, and extract the Cgminer.
5. I renamed the CGminer folder to just cgminer so it is easier to type in command prompt.
Install AMD drivers-
1. Open up terminal, and check to see if you extracted the AMD drivers to the right spot by typing :
ls
2. Once you see the driver file type
sudo chmod +x ./name of your AMD driver
3. To install the drivers type
sudo ./name of your AMD driver
4. Once the installer is finished reboot the PC
Set up CGminer-
1. Open up terminal, and install CGMiner required files.
sudo apt-get install libcurl4-openssl-dev pkg-config libtool libncurses5-dev
2. Change to cgminer folder
cd cgminer
3. Export your display settings
export DISPLAY=:0
export GPU_MAX_ALLOC_PERCENT=100
export GPU_USE_SYNC_OBJECTS=1
4. Check to see if CGminer detects all GPUs, and you can see the temps etc...
./cgminer -n
5. If all your GPUs show up you can go ahead and start mining. I started at a I of 9 to check stability of system
./cgminer --scrypt -o pool address -u workername -p password -I 9
6. If CGminer does not detect all GPUs type
sudo aticonfig --adapter=all -f --initial
Then restart PC
7. Export your display settings again, and retry
./cgminer -n
If all GPUs are detected start mining!
Lastly I recommend that you save a conf file using CGMiner, and you can edit your settings from that file instead of typing a huge command list every time you want to start mining.
For instance I have one set up with all my overclocking settings so I can just ./cgminer -c r9290 and CGminer loads up all my favorite settings.
Refer to the README files in CGminer if get stuck on the CGminer parts.
J
