I have tried very IRSTe and RST driver with my X79 Sabertooth in Achi mode, everything that was discussed in ths thread including buffer flushing enabled. It was horrid, only the MSACHI work at all and they still are very slow in the 4K write catagory. My new 840 Pro 512 in my 3960X system and I am not happy. I do have a question if I do not install the IRSTe driver and use the drive in MSACHI Mode is TRIM enabled? Anyone know of a driver that might work yet?