I'm having a strange issue. I've read the last several pages as well as searched via Google for several hours. No dice. Here's the issue:
I have 2 different GTX 970 rigs with 5 cards each. Testing them on ETH only mode. Before overclocking or anything, they all get about 18 Mh/s each. Here's the odd thing: 1 out of the 5 cards will be at around 11 MH/s.... i.e. GPU1. All speeds look equal in Afterburner. I'll restart the computer, and GPU1 will now be at 18 MH/s. But GPU2 will be down to 11. I'll restart the computer again. GPU0 will now be down to 11, all others at 18. So, it's not an issue with a card, because the dropped one changes on each restart. I have the same problem on both rigs. 1 card of 5 is always at 11-12 while the other 4 are at 18. One is an MSI board, the other is a brand new Biostar board. All have powered risers. I'll unplug one GPU, and just try with 4 GPU's. 1 card will be at 11-12, and other 3 at 18 MH/s. Restart, the slow card will be back at 18 but another card will be down to 11-12. It's driving me nuts! I downloaded the miner from Mega. One computer is running 9.7, the other 9.8. Same problem. So, it's not any particular GPU, not the miner version, not the motherboard, not the number of GPU's attached. What the heck is the problem? Somebody hacked into the miner?