Hope this is the right place to post this. I've had a rig running for a week now on 2 cards (for fun) and decided to add a third card. When I do this the cards don't seem to get going and cgminer shows all three cards at 15k, rather than the usual 500k
What I've tried thus far:
* Checked the new GPU works in a pair - all fine, card looks good
* Checked different PCI slots - they all seem fine
* Risers - Wondered if the risers were an issue, same problem with everything directly connected
* Three cards - Tried 3 cards in the rig but only two connected to the PSU. The two connected cards worked fine.
When I have three cards in the rig and all connected cgminder does see them all, just very very low speeds. It doesn't attempt to try and spin them up properly. If I use the -d flag on each card individually it runs at full speed.
Considerations:
Power - The PSU is 860W (Seasonic Platinum Series 860W). The rig is pulling 515 from the wall with 2 cards going at it.
Rig Specs
Power: Seasonic Platinum Series 860W
Cards: 3 x XFX Radeon HD 7970 DD Edition 3GB GDDR5 Graphics Card
RAM: Corsair Dominator DDR3 4Gb
CPU: Intel G1610 Celeron (2.6GHz, 2MB Cache Socket 1155)
M/Board: MSI Z77A-GD65 Motherboard
OS: Ubuntu
(Some of this kit was pullled from other systems I have)
So not sure where to go from here. Could it be a power issue? I thought the PSU would be OK with three cards and its only at 515. Could cgminer be the problem? It doesn't even seem to attempt to properly power the rig up. I've cut my cgminer settings back to minimal (no OC etc).
Thoughts welcome!
Cheers,