Can also confirm lost 2 MH/s total mining X11 combined with my 3x R9 270s and my 1x R9 280X on 14.9 drivers
All right, then I'm sure I fucked up my test somehow.
Did you delete the old .bin's from whatever drivers you had before, and had new ones generated for 14.9 drivers?
Of course I did. I'm gonna re-do the test now, though. 14.6 vs. 14.9 on both my X11 kernels.
Ooookay... this is odd. The hashrate changed - so it seems the driver did as well. Further, I fetched the date on fglrx each time before starting (14.6 being May 29 2014 and 14.9 being Sept 2 2014) so it DID change. As for the bin files, yes, I removed them; I double-checked. Anyway, Savage, this is what I've got, columns are GPU/clocks/mine/stock, rows are obviously GPUs.
Running driver version 14.6:
270X - 1155/1500 - 3.64 - 2.80
290X - 1045/1600 - 7.96 - 4.86
7950 - 1155/1500 - 5.03 - 4.01
280X - 1155/1500 - 5.77 - 4.54
Running driver version 14.9:
270X - 1155/1500 - 3.64 - 2.80
290X - 1045/1600 - 7.98 - 4.95
7950 - 1155/1500 - 5.03 - 4.05
280X - 1155/1500 - 5.75 - 4.60