Hi again, well after looking at these numbers once again, I've tried the only thing left to do, which was to get the second partition ended in both partition schemes equally, which was 31277055. Although I loose more space at the end now, I get full speed on both partitions. So, it seems that not only the starting sectors have to be aligned, but also the ending ones, or at least the ending one of the last partition. It's just quite strange that it has worked with MBR so well, as 31277231 + 1 isn't a multiple of 2048? Therefore it must be something inside of the controller, which is responsible for the bad result. As already said I'm using a Kingston S100 (quite new), can anyone confirm this (either on this SSD, or on any other)? If this is a general issue the partition programs have to be updated once again ;). I'm waiting for any response before submitting this upstream. Best regards, Karol Babioch