I don't think it's the OS any more, since there are no more errors. I am starting to think it's the power supplier. Even when running with power tune 15 and intensity 15 it shuts down after a few minutes when temps are around 50.
Seems to me that a 850W suppliers should support 2 cards drawing around 300W... Is there any app I can use to show how much power is drawn from the supplier?

I made some progress.
First of all, the crash was probably some compatibility problem between the pre-built cgminer version and xubuntu 12.04. I installed xubuntu 13.04 and managed to run cgminer.
Second, the remote running via ssh problem was solved (I think) using this guide:
http://devgurus.amd.com/thread/159566

Now I have a problem with the second card. This is the output from cgminer:

Can you see the picture i put above? It says "invalid picture" in my phone.

I did. It ran without any problems at about 20k per card.

The same power cable seems to be connected to both cards. Is this what you meant?

I tried booting with bamt 1.2 on a USB stick, but the computer shuts down after a minute before I have a chance to do anything. I didn't even start the miner.

going to try this for ssh:
http://wiki.tiker.net/OpenCLHowTo#Running_OpenCL_code_remotely_on_AMD_GPUs_.28via_SSH.29

I am not sure I understand your question. I ran BAMT from USB, is there another way? I didn't try with one card only.

I can't run cgminer via ssh. When I try to run it says "no device detected". I tried adding export DISPLAY=:0 before running and it didn't help.

I based it on this reddit thread and another one which I can't find.
http://www.reddit.com/r/litecoinmining/comments/1rurj5/what_are_your_r9_290_and_290x_settings/

running with 830 and 1500 doesn't crash the computer, but my x session freezes so I can't tell the hash rate. When i remote login via ssh the cgminer process seems to be running. Is there any way to tell the hashrate via ssh?
Am I supposed to run cgminer from within an x session?

These are my first tests with this rig, I never ran it for more than a minute.

Hi,
I am trying to mine on a machine with 2 r9 290 cards. I run cgminer and it starts without any errors, but after a few seconds of work my computer crashes and I have to restart it using the power button on the back.
I tried ubuntu 12.04 server 64 bit with xdm, then installed xubuntu on the server and also tried running batm from a usb stick. Same results.
I am using catalyst 13.12 linux drivers.
I am currently running the pre-built cgminer 3.7.2. I also tried building it from source but it segfaulted when I tried to start it.
I also installed app sdk 2.9 and adl sdk 6.0 when I tried to build cgminer.

I tried these cgminer configurations:
1. --scrypt -o stratum+tcp://gigahash.wemineltc.com:3333 -u <username>.1 -p <password> -g 1 -w 512 --lookup-gap 2 --thread-concurrency 24500 -I 20 --gpu-fan 70 --gpu-engine 947 --gpu-memclock 1250 --gpu-powertune 20

2.
{
"pools" : [
{
"url" : "stratum+tcp://gigahash.wemineltc.com:3333",
"user" : "<myuser>.1",
"pass" : "<mypassword>"
},
{
"url" : "stratum+tcp://usa2.wemineltc.com:3334",
"user" : "<myuser>",
"pass" : "<mypassword>"
}
],
"api-allow" : "W:127.0.0.1",
"api-listen" : true,
"scrypt" : true,
"gpu-threads" : "1",
"gpu-engine" : "1000",
"gpu-fan" : "75-100",
"gpu-memclock" : "1500",
"gpu-powertune" : "20",
"intensity" : "20",
"vectors" : "1",
"worksize" : "512",
"lookup-gap" : "2",
"thread-concurrency" : "24550"
}

3.
{
"pools" : [
{
"url" : "stratum+tcp://gigahash.wemineltc.com:3333",
"user" : "<myuser>.1",
"pass" : "<mypassword>"
},
{
"url" : "stratum+tcp://usa2.wemineltc.com:3334",
"user" : "<myuser>",
"pass" : "<mypassword>"
}
],

"intensity" : "20",
"vectors" : "1",
"worksize" : "256",
"lookup-gap" : "2",
"thread-concurrency" : "32765",
"gpu-engine" : "1000",
"gpu-fan" : "40-100",
"gpu-memclock" : "1350",
"gpu-powertune" : "20",
"temp-cutoff" : "99",
"temp-overheat" : "95",
"temp-target" : "90",

"api-port" : "4028",
"expiry" : "120",
"failover-only" : true,
"gpu-threads" : "1",

"log" : "5",
"queue" : "1",
"scan-time" : "60",
"temp-hysteresis" : "3",

"scrypt" : true,
"kernel" : "scrypt",
"kernel-path" : "/usr/local/bin"
}


I also tried with a 947 clock instead of 1000. same results.

This is my hardware configuration:

2 X Radeon R9 290 GPU - 4GB 512 bit DDR5 mem 21227-00-40G -Sapphire
GA-870A-UD3 Rev 2.0 - AMD 870 Chipset - GA-870A-UD3 -Gigabyte
AMD Athlon II X2 270 - 3200 MHz - 45nm -ADX270OCK23GM -AMD    
Gamma 50 Intel LGA775 and AMD socket AM2 Gamma-50 -DEEPCOOL    
4GB DDR3-1600MHz, PC3-12800, CL11-11-11- F3-1600C11S-4GNS -G-Skill    
500gb - 3.5 inch - 7200 RPM - SATA3 6Gb/    DT01ACA050 -Toshiba    
Cougar Solution Middle Tower Case - Dime    67M3-NPS -Cougar    
120mm Low Noise Sleeve bearing fans - 4-   R4-S2S-124K-GP -Coolermaster    
OCZ850GXSSLI - 850W PSU - OCZ

Thanks.