Quote from: padrino on July 10, 2011, 12:07:45 AM

Quote from: jondecker76 on July 09, 2011, 09:41:13 PM

Quote

Is here any reason why Automatic profile mining 20 Mhash/sec more?
is it just rounding in formula or dbase distributing load better?
Rejection rate with automatic profile is horrible, more workers, more rejections,
maybe it is compensation for higher hashrate.

I have found that I get a slight increase in hashing with multiple instances. I have seen the explanation that multiple instances help fill in very small times where the CPU might be waiting for the GPU before sending it new work, hence the slight increase in hashing with multiple instances as the CPU always has somewhere to send work to without waiting.

I don't get any rejection rate problems, no matter how many instances I happen to be running. I have tested this up to 6 instances per card with no real affect on rejections. I have found, however that worksize is very important when it comes to multiple instances and rejection rate. Could you go to configure miners->edit and edit the phoenix launch string, changing the work size from 128 to 256, then restart smartcoin. I'd be interested to hear if it fixes your rejection rate problems (i run worksize 256 and I'm always below 1%). I've been thinking about changing the default launch string to 256, your confirmation on this could help me make that decision.

The worksize will affect performance depending on your memory clock generally speaking a worksize of 256 will be best with a memory clock around 300Mhz. I actually run that way because you don't need your GPU memory for much while hashing and this keeps the power consumption and heat lower.

On my 6970's 950/300 if I set my worksize to 256 my Mhash/s goes down. I have to run at 128.