spang1974 Posted March 30, 2014 Share Posted March 30, 2014 My USB 3.0 was working properly (since I first built it) with Mountain Lion 10.8.2 (without GenericUSBXHCI) and was reading and writing at speeds greater than I got with USB 2.0, it was not an issue to backup 300-400GB to my external USB 3.0 drive. Unfortunately once I updated to Mavericks 10.9.0 the write speeds dropped to under 20Mb/s. I ended up not noticing this until I updated to 10.9.2 and decided to do a clean complete backup with Time Machine. The drive is still recognised as USB3.0 and says it's capable of "Up to 5 Gb/sec" instead of the "Up to 480 Mb/sec" , I realise speeds are never this high. The USB 3.0 drive actually gets better speeds from my USB2.0 ports, yet still not as high as they were with Mountain Lion. I have tried using the different versions of GenericUSBXHCI.kext and without it. I soon as I had a chance I reinstalled 10.8.2 on a test system, and the drive immediately started writing at speeds greater than 80Mb/s. I then upgraded to 10.9.0 on my test system and the drive went back to writing at under 20Mb/s. So anybody have any advice? I was wondering if anyone else had noticed if their USB 3.0 was actually working properly? Is it just this motherboard? Am I using the wrong kext? Did I need to change any bios settings once I updated to 10.9? Spang1974 Link to comment Share on other sites More sharing options...
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