Hi at all, i running into some strange behavior with those drives. First i thought it is the controller , changed it , changed the system , used AHCI SATA Intel chipset ports. On every system/combination the same issue. The drive D has the problem that i cannot enable the write cache of the device itself. the second drive has no problem with enabling or disabling it. so i benchmarked drive E with both settings. the bench in the middle show with activated write cache , the right one without. so the behavior is similar to the left benchmark (drive D). i checked the PCB of both drives , the look absolutely identical. The Firmware are also the same on all drive. i have 7 of those drive with this issue and 3 without. one of the "defective" drives is 9 days old, the other one has run already 510 day but Harddisk Sentinel says 100% excellent status on both drive. i tryed also to switch the PCBs, but the drives won't came up in the device manager. have anyone of you run into same issues ? any ideas ? Thanks all in forward.