Bitcoin Forum

2 different cards with different hashrate

1 system (linux ubuntu 12.04)

what is the best?

1 cgminer with both cards in the same config file
or 2 cgminer's with different workers and different config files?

1 cgminer with settings specific to each card - just separate each setting with a comma eg.

cgminer --scrypt --url http://p2pool.bbqcoin.darkgamex.ch:19324/static/ --user x --pass x --expiry 30 --gpu-threads 1 --worksize 256 --intensity 19,18 --thread-concurrency 18512,7168 --gpu-engine 880,850 --gpu-memclock 1500,1200

The only time I have had to run 2 instances of cgminer is when the cards use different --gpu-threads.

If you plan on mining the same coin with both cards I would recommend to use 1 instance of cgminer configured with 1 worker.  You can specify settings for each card in the config file, for example "thread-concurrency" : "8196,22400".  If you are unsure which card is which, you can start cgminer with the flag -n to list all the cards.

But if you have a vardiff pool?

Is it switching for the best card or is is switching for both cards the best settings?

Good call, perhaps for that specification it is best to use 2 instances of cgminer.  However who is to say that they will not be doing the same work?  I have not done such a thing but you have sparked my interest and I may attempt it.  Perhaps I could mine multiple coins with one rig?

with vardiff 2 instances with 2 workers is the best bet. even without vardiff it can be better if the cards are say a 7770 and a 280x since their hashrates are so far apart