Post
Topic
Board CPU/GPU Bitcoin mining hardware
Re: Graphics cards locking up - why so randomly?
by
Nancarrow
on 02/04/2012, 17:04:50 UTC
It isn't black or white.  STABLE vs UNSTABLE.  It is a gradient (hypothetical numbers):

Well, yes I do realise it isn't black or white, my question was really trying to ask 'WHY isn't it black and white?' Having said that, I can kind of think of an answer. It's (waves hand around vaguely) quantum mechanics, which if memory serves me correctly, is supposed to be based on fundamentally random processes anyway. Electronic processes are quantum processes, so I guess for each given hash there is a probability that the answer will be garbage, and I suppose that as a function of clock speed, this probability goes up in a probably vaguely sigmoid-looking way.

Quote
Another thing to look for (in cgminer) is HW errors.  Those are caused by the card returning garbage as "work completed".  It is a good sign the GPU is redlining and is right on the edge of stability.

Now that sounds like a good idea. I use BAMT, which I understand has cgminer as an option. Is there a good reason why the author steers newbs towards Phoenix and away from cgminer?

Also, how exactly does the GPU go from 'giving stupid answers' to 'not functioning anymore'? Is there something in the drivers that checks for computing errors and shuts it down if there's too many? Or is it in the miner software? And how can I disable such a process (even at the cost of getting loads of rejected shares)?