Hey guys! First time post but I've been following this thread for awhile. I just purchased and installed the Syba I/O Crest SI-PEX40129 in my mid 2010 Mac Pro. Before with the regular adapter I was getting around 1,400 read and write but now I'm only getting an increase of 1,800 write and around 2,500 read for some reason. I've tried both 16x slots as well. Any ideas?? This was an expensive purchase and I'd really like to get this resolved.
Also, speeds seem to be very inconsistent. For examples it can go from 1,800 write and go as low as 800-900. This happened with the old adapter too.