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Author Topic: Cannot mine from second card -  (Read 1026 times)
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July 20, 2011, 07:23:24 PM

Hi, hoping to understand why I cannot use a second GPU on a mining rig:

Used this as a basis for my mining rig:  (Two ATI 5850s, Approximately 600 Mhash/s)

900 W power supply
MSI 870-G45  motherboard
2x XFX 6850 - 1GB GPUs
400 GB HD

I installed ubuntu 11.04 and all of the software as documented in this post:

poclbm works fine on the first GPU (-d0) and on the CPU (-d2) and can see both devices

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 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

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July 23, 2011, 03:44:29 PM

The 4x won't matter. All you need is 1x.

To be honest, I'd quickly return both of those 6850's for 3x 5770's or any of the 58xx series. If you can't find those, then 6950 would work.

Here's why:

Qty*card = total mh/s @ total price

2x6850 = 420mh/s @ 300 dollars
3x5770 = 600mh/s @ 270-330 dollars
1x6950 = 350mh/s @ 190-230 dollars. (Plus these will retain a better value in the future)

As for you problem, have you tried linuxcoin? Everything is all set up. It sounds like you have a lot of crashing going on, perhaps reinstall the software?

Your hardware set up will work. Also with that big of a PSU, you can easily run 4 cards if you had a different mobo. -- First PPS SiaMining Pool! 3%, VarDiff, Stratum Support
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July 23, 2011, 06:36:51 PM

Your config should work. I have 2 at 8x and 1 at 4x with no problems.

If there is a molex connector on the motherboard and you have a molex plugged into it, remove the plug. I don't know why but this made it so my MB would only see one card. Only use the power that plugs directly into the cards.

If that doesn't solve it, take out both of the cards and put them in one at a time into each slot and reboot to ensure that the slot is working. If there are any slots that don't work, you might have a defective motherboard.

After this, put in all of the cards. Switch positions for the two cards. If the card that is not mining high still is not working, then it's a problem with the card. RMA it.

If you still have a problem with both cards but in the same slot, install the latest drivers for your motherboard. Wipe out all ATI software and drivers using these instructions. Reinstall catalyst.

At this point it should work.

If this post helped you, please donate some btc : 1KZnfWkXXLdEjvQKYALbEsjbeWpvSG9NWB
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