Issues with new mining rig. 2x 6879 + 1x 6850

[mazedk]

Hi guys

My new/re-use ltc mining rig is causing me some issues.. I've got the 6850 running in the 16x socket on my motherboard. The 2x 6870 are running in 1x to 16x risers' non powered.

It's however like cgminer fails/crashes whenever I want to bring the 6870's up and running. Running the 6850 alone has itmhashing away. Right now I only have 1 of those connected to the psu. But do I really need to get a powered riser?

If I use the bitminter java client it hashes at 25-30mh/s while the 6850 is running 200ish mh/s..

Any thoughts?