Hello all,
My mining rig has 3x Sapphire 7950's, my OS is Xubuntu 12.10 and I'm using cgminer. All of the GPUs are undervolted to 1081 mV.
I'm having a strange problem: The 2nd GPU, which is between the other two, has a significant lower hash rate than the others!
cgminer version 3.7.2 - Started: [2014-02-09 12:31:05]
--------------------------------------------------------------------------------
(5s):1.767M (avg):1.724Mh/s | A:34426 R:2652 HW:0 WU:1541.5/m
ST: 2 SS: 0 NB: 21 LW: 248 GF: 0 RF: 0
Connected to stratum.fast-pool.com diff 839 with stratum as user bomberb17.1
Block: 5703c08d... Diff:1.39K Started: [12:49:57] Best share: 85.6K
--------------------------------------------------------------------------------
[P]ool management [G]PU management [S]ettings [D]isplay options [Q]uit
GPU 0: 76.9C 2542RPM | 613.0K/595.6Kh/s | A:14435 R: 326 HW:0 WU: 525.5/m I:20
GPU 1: 77.2C 2576RPM | 521.8K/541.0Kh/s | A: 9151 R:2000 HW:0 WU: 504.7/m I:20
GPU 2: 60.5C 1988RPM | 607.6K/591.3Kh/s | A:11678 R: 326 HW:0 WU: 526.6/m I:20
--------------------------------------------------------------------------------
My cgminer settings are
cgminer --scrypt -o stratum+tcp://stratum.fast-pool.com:3002 -u bomberb17.1 -p 1 -I 20 --thread-concurrency 24000 --gpu-engine 1050 --gpu-memclock 1500 --worksize 256 -g 1 --lookup-gap 2
I tried to change its clock settings from within cgminer, but I see that it is clocked lower than the other 2!
So when I hit 'G' for [G]PU management I get
GPU 0: 603.2 / 595.2 Kh/s | A:20 R:1 HW:0 U:0.83/m I:20
76.8 C F: 59% (2537 RPM) E: 1050 MHz M: 1500 Mhz V: 1.081V A: 99% P: 0%
Last initialised: [2014-02-09 12:31:05]
Intensity: 20
Thread 0: 602.1 Kh/s Enabled ALIVE
GPU 1: 561.0 / 541.0 Kh/s | A:16 R:1 HW:0 U:0.66/m I:20
77.4 C F: 59% (2581 RPM) E: 850 MHz M: 1250 Mhz V: 1.081V A: 100% P: 0%
Last initialised: [2014-02-09 12:31:06]
Intensity: 20
Thread 1: 560.2 Kh/s Enabled ALIVE
GPU 2: 607.8 / 592.3 Kh/s | A:23 R:1 HW:0 U:0.95/m I:20
60.2 C F: 48% (1982 RPM) E: 1050 MHz M: 1500 Mhz V: 1.081V A: 99% P: 0%
Last initialised: [2014-02-09 12:31:06]
Intensity: 20
Thread 2: 611.6 Kh/s Enabled ALIVE
I then try to change its clock settings, it changes to 1050/1500 for a few seconds then it goes back to 850/1250!
Any ideas to solve this???
