Yep, this version doesn't work right with NScrypt and 14.1 drivers.
Here's the same config with 13.12 drivers. Still not ideal, but better.

Yeah I'm on 13.12 drivers and I refuse to upgrade. You might need to start looking at different TC's to tweak the speed. I've seen a number of 290 configs using TC 32765
I used to have 24550 on my 290's, but the 2% rejects started to bother me regardless of how great the hashrate was. I changed it to 25600 and now my reject % is below .5%.