My experiments with R9 280X (1100/1250) and version 9,1:
primorial 14
[GPU 0] T=64C A=97% E=0 primes=0.104240 fermat=709830/sec cpd=9.29/day
(ST/INV/DUP): 1x 9ch(0/0/0)
Work received: height=736596 diff=10.976544 latency=169ms
Work received: height=736597 diff=10.976542 latency=167ms
[GPU 0] T=65C A=97% E=0 primes=0.104230 fermat=700775/sec cpd=9.16/day
(ST/INV/DUP): 1x 9ch(0/0/0)
Work received: height=736598 diff=10.976527 latency=167ms
Work received: height=736599 diff=10.976546 latency=170ms
[GPU 0] T=64C A=95% E=0 primes=0.104253 fermat=708750/sec cpd=9.29/day
(ST/INV/DUP): 1x 9ch(0/0/0)
primorial 13
[GPU 0] T=64C A=95% E=0 primes=0.105844 fermat=610418/sec cpd=9.31/day
(ST/INV/DUP): 1x 10ch(0/0/0)
[GPU 0] T=65C A=97% E=0 primes=0.105879 fermat=622893/sec cpd=9.53/day
(ST/INV/DUP): 1x 10ch(0/0/0)
[GPU 0] T=65C A=97% E=0 primes=0.105916 fermat=617762/sec cpd=9.48/day
(ST/INV/DUP): 1x 10ch(0/0/0)
Work received: height=736534 diff=10.976459 latency=172ms
Work received: height=736535 diff=10.976453 latency=172ms
primorial 12
Work received: height=736542 diff=10.976462 latency=173ms
[GPU 0] T=65C A=95% E=0 primes=0.107466 fermat=497988/sec cpd=8.84/day
(ST/INV/DUP): none
Work received: height=736543 diff=10.976461 latency=172ms
Work received: height=736544 diff=10.976463 latency=175ms
[GPU 0] T=65C A=94% E=0 primes=0.107517 fermat=493357/sec cpd=8.80/day
(ST/INV/DUP): none
primorial 13 is optimal, trying change weave depth to 38912:
[GPU 0] T=65C A=97% E=0 primes=0.105512 fermat=650201/sec cpd=9.61/day
(ST/INV/DUP): 3x 9ch(0/0/0)
Work received: height=736833 diff=10.976756 latency=175ms
Work received: height=736834 diff=10.976754 latency=172ms
[GPU 0] T=65C A=97% E=0 primes=0.105512 fermat=650914/sec cpd=9.62/day
(ST/INV/DUP): 3x 9ch(0/0/0)
Work received: height=736835 diff=10.976758 latency=176ms
[GPU 0] T=65C A=97% E=0 primes=0.105516 fermat=651608/sec cpd=9.63/day
(ST/INV/DUP): 3x 9ch(0/0/0)
Memory overclocking to 1500 test:
[GPU 0] T=66C A=97% E=0 primes=0.105486 fermat=662313/sec cpd=9.76/day
(ST/INV/DUP): none
[GPU 0] T=66C A=97% E=0 primes=0.105513 fermat=661911/sec cpd=9.78/day
(ST/INV/DUP): none
You can reach ~9,8CPD on R9 280X @ 1100/1500 with primorial = 13 and weave depth = 38912