Hi everyone.
I've finally decided to post here, because I've been fighting for days with my GPUs trying to tune them to get decent hashrates (or at least something that looks like what I could find from various sources like
https://litecoin.info/Mining_hardware_comparison or
https://bitcointalksearch.org/topic/consolidated-litecoin-mining-guide-for-5xxx-6xxx-and-7xxx-gpus-117221 ) and miserably failed. So I need some advices from more experimented miners ...
I have two machines, both are running quite similar software setup : Win7 64 bits, Catalyst 13.12 drivers and cgminer 3.7.2.
First system has a HD6950 with reactivated shaders (so 1536 SP like in a 6970) clocked at 840/1250. This is the system I have experimented the most with settings and my current cgminer command looks like this : --intensity 12 -g 1 --thread-concurrency 4032
This setup shows about 240 kH/s according to cgminer.
The problem is that I can't get any close to the recommended settings of 4*SP count for thread concurrency (6144) or to what I can find on the page linked above (between 6144 and 8192). If I set anything higher than 4032, cgminer will refuse to start with a -4 error.
I have the same problem with intensity setting : at intensity 12, I get a few HW errors (I get none at intenisty 10), but I won't be able to set anything like those found in examples (instensities up to 18 or 19).
What am I doing wrong ?
Are people reporting higher hashrates (in the 450's) with aggressive setting only lying about their parameters, and are only doing so to report big numbers, but with nothing productive (tons of HW errors and no valid work accepted) ?
The same questions and situation apply to my other machine with a R9 290X (allowing +50% of power draw and fan up to 100%). I'm only able to use these settings : --intensity 14 -g 1 --thread-concurrency 16384 which produce 635 kH/s ...
This is quite far from the numbers I found (intensity 18-20, thread concurrency between 24000 and 32768 which should give hashreate in the 800's).
Any thoughts or advice are welcome.