Hello,

I have 5 Sapphire 3L 7950s on one motherboard with powered rises on all of them. 3 of them are 16x to 16x and two are 1x to 16x...i started having really bad stability issues out of the blue tonight on settings i had been using for the last week without issues. Drivers started crashing constantly (im on windows), so i re-installed the proper drivers and was still having issues. So i went to disconnect one of the cards and realized the 12 volt cable in my molex power adapter on the riser had come loose. I re-attached it and my rig is now somewhat stable, but still not what it was. (i was running vddc 1075, gpu code 1025 gpu mem 1575 all week)

Anyway I notice when i go into Trixx (overclocking software) the voltage on the 3 pcie 16x to 16x cards have a default vddc of 1.250v  (i am currently undervolting to 1.075v with gpu core at 1000 and mem 1400) but the weird thing is the two 1x to 16x default to a vddc between 1.116v or 1.160v. Is this because the powered risers aren't working properly? Here is the link to the risers I bought, and insight would be much appreciated.

http://www.amazon.com/PCIe-1x-Extender-Bitcoin-Mining/dp/B00D35G02G/ref=sr_1_23?ie=UTF8&qid=1371981236&sr=8-23&keywords=pcie+1x+to+16x