I have some new info, well old for me. I should have posted here earlier.
I got a few more of these cards and found that they had different memory manufacturers, thus needing different params to run. The 8192 tc and 2 threads seems to be the correct setting but the VRMs were running at 110 degrees! hot as hell. You guys need to load GPU-Z and check the VRM temps of your cards. If you haven't flashed them with optimized bioses from the litecoin forums you may be burning up your cards.
After identifying the memory as Elpida I found modded bioses by a user named Stilt. You can find them here :
https://litecointalk.org/index.php?topic=12369.msg93754#msg93754That thread has all the information you need to know to correct this problem. With the modded bios my VRMS (voltage regulators) are running at 60 degrees. The memory settings are also tweaked nicely for 1500/1044 allowing for undervolting 1.088 or less. The cards run quiet, cool, efficient and produce 725Kh/s with these settings.
--lookup-gap 2 --thread-concurrency 11280 -g 2 -I 13 -w 256 --expiry 1 --scan-time 1 --queue 0 --no-submit-stale
Memory 1500
Core 1044
VDDC 1.088