That's interesting.  I'm struggling with this problem now with a 2x 7950 rig.  Even Intensity 13 is giving me some errors.

I have 4Gig RAM, so maybe I'll pick up 4 more... 

Can you post if you notice you are getting errors again.

Thanks,
 

Are you using Reaper or CGMiner? I have two rigs with 3x7970s and they work fine with 4GB of ram at an intensity of 20. Cgminer, Win 7.

I'm sure you meant 8192.
did you verify the command worked, and is spelled right?
(if you're on windows, check your environment variables. right click my computer, advanced system settings, environment variables, it should show up in the top pane.)

AFAIK, the difference in threads makes no tangible difference in most cases...and i have yet to get a card to work above 10240 concurrency with 2 threads... not that i need to, 1 or 2 threads at 8192 gives me the same speeds.

I ran 12.10 for a long time, despite everyone (and tacotime) saying it was bad for LTC mining. I run 12.8 on both boxes, and whatever SDK came with it.

One thing i DID notice recently, the High intensities don't play well FOR ME with lower work sizes. 64/128 at any intensity >13 gave me 50-60kh/s lower than 256 work size.

As always YMMV.

Edit : Sorry coingarbler, i dont dabble in linux.