Mac 5,1 Xeon 3,33Ghz 24Gb Ram 1333Mhz Mercury Accelsior 240Gb Yosemite 10.10.1 Latest OWC drivers installed properly The machine has hmm 2 years and a half. Software: BM Speed test. I remember having both read and write values way above 600 Mb/s (with Mountain Lion)... Now, read speed is always fine (600 and above) but write never goes above 300. What can it be? Thanks for your help!