Random GPU OFF on mining scrypt-nfactor with 6x270 cards

[yinhm]

reproduce:

• Windows 7 x64, 4GB System Memory
• 6xMSI270 rig, 6xHIS270 rig
• sgminer v20140311 [1]
• start sgminer with random GPU cards showing "OFF"
• Config:

"intensity": "19",
"worksize": "256",
"kernel": "psw",
"vectors": "1",
"nfactor": "11",
"lookup-gap": "2",
"gpu-engine": "900-1070,900-1070,900-1070,900-1070,900-1070,900-1070",
"gpu-memclock": "1460,1460,1460,1460,1460,1460",
"thread-concurrency" : "10241",
"shaders" : "1280,1280,1280,1280,1280,1280",
"gpu-powertune" : "20",
"gpu-threads" : "1",

After upgrading both rigs to 8GB system memory, problem goes away, even thought that Windows only use 1GB of system memory.

Note:

• We could start 3 sgminer instances with specific cards on for each instance without problem.
• We could lower the "thread-concurrency" to get all cards running without problem, but it can't archieve the optimal hashing rate.

This problem also applys to TheKev's Miner [2].

[1] sgminer windows compiled: http://cryptojournal.blogspot.com/2014/03/sgminer-windows-compiled-on-20140311.html [2] NEW THEKEV VERTMINER: https://bitcointalk.org/index.php?topic=466867.0;all

[veox]

A few notes about the config:

• don't use nfactor directly, use algorithm (see doc/configuration.md);
• setting both shaders and thread concurrency is excessive ATM, try without shaders;
• it is best to run with 2 gpu-threads per card (and lower intensity), see #117.

[Zuikkis]

Yes.

"xintensity": "4", "thread-concurrency" : "5121", "gpu-threads" : "2",

Should be good for 270.. Gives me 250kh/s with vertcoin, 1123/1250 clocks.

[acuvic]

Thanks Zuikkis

I use a 270 (just tryin out till I've saved enough) but got rejects till I used your settings. Now getting 230kh/s, HW:0 on SGminer using the Nscrypt.bat, 1035/1400 clocks

On vertminer with a lot of experimenting, only got 190kh/s with 4-5 errors per hour.

[poiuty]

"kernel": "alexkarold", "xintensity" : "4", "algorithm" : "adaptive-n-factor", "lookup-gap" : "2", "worksize" : "256", "thread-concurrency" : "5121", "gpu-threads" : "2", "gpu-powertune" : "0", "gpu-engine" : "1160", "gpu-memclock" : "1250",

get 250kh/s some cards need gpu-engine 1120~1140

[veox]

Should this issue be closed as a misconfiguration?

[yinhm]

@veox Yes, please. I got 240KH/s as @Zuikkis indicated, guess system memory was a mislead.