cgminer a bit erratic

[fc_flumpker]

Running a 7970 in Windows 7/64.  I'm seeing some erratic behavior in cgminer and I'd appreciate some insight.  Randomly, cgminer appears to just stop doing anything.  No errors or anything, it just stops and the screen doesn't move.  This happens with FTC.  I also notice that while it is mining, video performance is spotty (blocks of blank pixels).  I'm not so worried about it since I don't need to use the box for anything else. 

When I tried once to do BTC, it ran for a minute then the video card just went nite-nite knocking out the power supply.  (I have it setup with a Antec 550W Plus psu just powering the video card - the PC is an HP Z400 with its stock psu powering everything else). 


I'm using the following for FTC
cgminer -o http://p2pool.org:9377 -u user -p pass --scrypt --intensity 15 -g 1 -w 256 --thread-concurrency 8192 --gpu-engine 1000 --gpu-memclock 1350

Here is the BTC config I tried:
cgminer -o stratum.btcguild.com:3333 -u user -p pass --intensity 15 -g 1 -w 256 --thread-concurrency 8192 --gpu-engine 1000 --gpu-memclock 1350

[1713969968]

1713969968

[JesstersDead]

With a 7970(I run 4) it has been my experiance that anything above I 13 can cause a lot of hardware errors. Typically this only happened at -g 2, but I did get increased hardware errors with -g 1 as well. Personally I found the sweet spot for my WF 7970's was I 13, -g 2, TC 12000, w 256, and clocks at 1025/1500 w/ vddc @ 1100mv and powertune adjusted for heat/stability.

[fc_flumpker]

Just changing to I 13 bumped me up to 485Kh/s.  What is the -w for?  I don't think I see that in the --help.

[JesstersDead]

--worksize|-w <arg> Override detected optimal worksize - one value or comma separated list

[JesstersDead]

You should be able to get 650+ out of your 7970 fairly easily. Mine average about 720 kh/s with the above stats. And since the intensity is low the PC's in question are still usable for web browsing etc.

[fc_flumpker]

I'm at 610Mh/s with:
cgminer -o stratum.btcguild.com:3333 -u user -p x --intensity 13 -g 1 -w 256 --thread-concurrency 12000 --gpu-engine 1025 --gpu-memclock 1500

and the fan is manually set to 70% and the temp is at 73C.

[fc_flumpker]

That didn't last long.  In about 5 minutes, the video card went out again.