cgminer questions (help me understand)

[qiuness]

Hello,

I`ve been reading tens and tens of pages but some things are not explained that good. So maybe someone can help me make sens of them:
I`m mining Litecoin btw...


1. When you use --thread-concurrency do you also need to use --shaders? Do one exclude the other?
2. the -g 1 at the end, i`ve seen some configs with -g 2... What are the requirements... or is it more trial and error/
3. When setting --gpu-fan xxx, the setting does not always take. What are the requirements for it to take?
4. How on earth do you run 2 instances of cgminer if you have different class cards in the rig?
5. In the consolidated mining thread there is this reference:
"Set thread_concurrency to somewhere slightly below 64 * bus_width_of_card_in_bits.  So, for a 7950, that would be 64 * 384 = 24576; ideal values are 21712 or 24000"
If that is true then why do some of my sapphires only work with 16384.. anything more gives me a -5 error

Thanks!

[Protagonus]

I'll try to help where I can. I'm pretty new still, but there seems a lack of people to help.

1. NO  Shaders are used as a baseline to help setup the cgminer.  Concurrency is more of the fine tuning.  You can have both or either; up to you. 
(Shaders are the hard set number on your GPU, whereas concurrency is a multiple "usually" of the shaders dealing with GPU RAM usage)

2. The -g is a "last step" item you can play with yes.  Most of the time (from what I understand) use -g 1.  Higher G may require lower -I

3. Fan I can't help there;  I use afterburner, vision center, trixx etc for fan speed.

4. not sure on multiples either.  Do you get an error with the second?  if not, try 2 cgminer folders with separate .bats (one for each gpu)  Some programs you can add "-multiple" tag at the end of the file target.
 
5. You need to set the system to accept higher concurrency values.  Open a terminal and type: setx GPU_MAX_ALLOC_PERCENT 100 (assuming windows OS here)

Hope this helps

PS- look for  a readme file in your CGminer folder

[qiuness]

hey thanks for the answers.
I figured out fan control. Now it is a matter of tweaking

[FloridaBear]

I've played a lot with tweaking on my 7970. I typically leave the fan at a constant rate and have cgminer alter the core speed:
--gpu-fan 85 --temp-target 80 --auto-gpu --gpu-engine 750-1140

I am unable to set my memclock less than 150MHz under my core; so I use
--gpu-memdiff -150 to always keep it 150MHz under the core.

For scrypt mining (based on the docs), thread-concurrency overrides shaders (you don't need both). For most cards, you want thread concurrency of 4*shaders (8192 for 7970). My settings:
--scrypt --thread-concurrency 8192  -I 13 -g 2 -w 256 --gpu-engine 500-1080 --gpu-memclock 1500 --gpu-fan 85 --temp-target 81 --auto-gpu --temp-overheat 87

Constant memclock at 1500 (best for this particular card), vary engine from 500-1080 to maintain 81C. Fan constant at 85%.

Hope that helps!

[go4gonzo]

I've played a lot with tweaking on my 7970. I typically leave the fan at a constant rate and have cgminer alter the core speed:
--gpu-fan 85 --temp-target 80 --auto-gpu --gpu-engine 750-1140

I am unable to set my memclock less than 150MHz under my core; so I use
--gpu-memdiff -150 to always keep it 150MHz under the core.

For scrypt mining (based on the docs), thread-concurrency overrides shaders (you don't need both). For most cards, you want thread concurrency of 4*shaders (8192 for 7970). My settings:
--scrypt --thread-concurrency 8192  -I 13 -g 2 -w 256 --gpu-engine 500-1080 --gpu-memclock 1500 --gpu-fan 85 --temp-target 81 --auto-gpu --temp-overheat 87

Constant memclock at 1500 (best for this particular card), vary engine from 500-1080 to maintain 81C. Fan constant at 85%.

Hope that helps!

Good stuff. A lot of understandable info here. thanks everyone!