7970 litecoin hashrate problem.

[sweeppicking]

Hi every one! i'm new in the forum, i read a LOT of info about how to config a 7970 to achieve the +700khs in litecoin mining.
I have 3 sapphire 7970 in CF, one reference PCB and two Dual X dual DVI.
After searching so much info about it, i seems like is so hard to push this card to the limit, some people can get 720khs with the sapphire Dual x cards.
I see that i need to use -g 2 and find the exact relation with GPU engine and memmclock to rise the hash, but still i can't get more of 650 khs.
I have a watercooled system for the cards and i'm runing it with a FX 8350 in 5ghz.
I also read the CGminer Scrypt Read me and this was what i done:
 i can't use Intensity more or less than 13, if i use >13 my hashes go down, if i use <13 same.
Thread concurrency only make me need more GPU engine to get the same hash.
So, can anyone help me with this?
I think so many paople has the exact same problem.
Thanks for all and sorry for bad english.

[blastbob]

This works very well for me, stable around 75C@2100RPM on all adapters (ASUS Radeon HD 7970 3GB GDDR5 - DirectCU II TOP)

The card hash result differ from the cards i have in windows vs linux. Linux seems be a little better on this.

cgminer --scrypt -o stratum+tcp://pool -u user -p pass --worksize 256 -g 2 -I 13 --lookup-gap 2 --gpu-engine 1065 --gpu-memclock 1500 --shaders 2048

[sweeppicking]

This works very well for me, stable around 75C@2100RPM on all adapters (ASUS Radeon HD 7970 3GB GDDR5 - DirectCU II TOP)

The card hash result differ from the cards i have in windows vs linux. Linux seems be a little better on this.

cgminer --scrypt -o stratum+tcp://pool -u user -p pass --worksize 256 -g 2 -I 13 --lookup-gap 2 --gpu-engine 1065 --gpu-memclock 1500 --shaders 2048

You aren't using thread concurrency, what is your hash rate?
Why you use that engine/memmory config and how you find it?

[blastbob]

I usually gets lower output when i mess with threads.

I am getting ~720 on linux and ~660 on windows 7 64

The engine memory part is what i found worked best for me. I can tune it a little higher, but i got some unstability and noise problems

Make sure you use the latest cgminer, 2.11.4 it should be.

[hakushka]

1043/1500 gives me about 733 KHash (cgminer 2.11.4 or 3.1 does not matter)

[JimmyFL]

--shaders 2048 --thread-concurrency 8192 -I 13 -g 2 -w 256 --auto-fan --gpu-engine 1080 --gpu-memclock 1500 --temp-overheat 80

==> 750kh/s, max 73C (windows)