Hi, hoping to understand why I cannot use a second GPU on a mining rig:
Used this as a basis for my mining rig:
https://en.bitcoin.it/wiki/Mining_rig (Two ATI 5850s, Approximately 600 Mhash/s)
900 W power supply
MSI 870-G45 motherboard
2 GB DDR3 RAM
CPU AMD SEMPRON 140
2x XFX 6850 - 1GB GPUs
400 GB HD
I installed ubuntu 11.04 and all of the software as documented in this post:
http://forum.bitcoin.org/index.php?topic=7514.msg110334#msg110334 poclbm works fine on the first GPU (-d0) and on the CPU (-d2) and can see both devices
~/bitcoin/logs$ poclbm.py
No device specified or device not found, use -d to specify one of the following
[0] Barts
[1] Barts
[2] AMD Sempron(tm) 140 Processor
I did run aticonfig --initial -f --adapters=all
If I stop all poclbm and then run poclbm on the second GPU (-d1) it will connect to the pool but does not start any processing. CTRL-C and kill does not stop the poclbm and kill -9 crashes the entire computer. Once poclbm -d is run any software "reboot"" will crash the computer as well.
In googling around, I found that the motherboard physically has 2 x16 slots, but one is x4? I know linux pretty qell, but don't know PCI-e too well.
From msi.com for the mobo:
PCI-Ex16: 2
PCI-E Gen: Gen2 (1x16, 1x4)
Questions: Should this configuration work? If so, how can I troubleshoot it?
~/bitcoin/logs$ aticonfig --pplib-cmd "get activity"
Current Activity is Core Clock: 875MHZ
Memory Clock: 1000MHZ
VDDC: 1150
Activity: 99 percent
Performance Level: 2
Bus Speed: 5000
Bus Lanes: 16
Maximum Bus Lanes: 16
~/bitcoin/logs$ DISPLAY=:0.1
~/bitcoin/logs$ aticonfig --pplib-cmd "get activity"
Current Activity is Core Clock: 300MHZ
Memory Clock: 300MHZ
VDDC: 950
Activity: 0 percent
Performance Level: 0
Bus Speed: 2500
Bus Lanes: 4
Maximum Bus Lanes: 16