R9 270 no x (Official name is GV-R927OC-2GD revision 1.0)
Settings for 428kh = cgminer.exe --scrypt -I 16 --thread-concurrency 12000 --gpu-engine 1125 --gpu-memclock 1500
I can up the intensity to 19 which makes it goto 470-480kh but cgminer would eventually crash an hour later, temps look fine but hardware errors would emerge at intensity 17,18,19 and crash so Intensity 16 is highest i can go at the moment.
Seen some others online stable at 450kh, which is intensity 17 for my settings but it crashes for me there.
Using Windows 7, might try Linux to see if i can stabilize it better there
http://abload.de/img/cgminerxlur7.jpghttp://abload.de/img/cgminerxlur7.jpg