I found the same problem initially with the new Claymore miner. I had to do a few hard resets and massage the memory and power tune settings compared to the optiminer settings but after a bit of trial and error I managed to get it all going good.

As tytanick said try to lower the settings or reset to stock and reboot to get a stable.
I have found that Claymore cannot handle the higher clock settings that optiminer could handle but after playing around for a bit can still get better hashrate with Claymore with lower clock speeds.
Im mining with 2 rigs running 7970/280x and another rig running r9 290's