Fast Write. Fast writes allows the CPU to send data to the Graphics card without having to go through RAM, making it a far more optimal approach. That said in reality most benchmarks done on this have shown it to be of little actual benefit, in some cases performing slower, not mention on other systems it causes stability problems. As a result you might want to run a few benchmarks before choosing whether or not to leave this On or Off. On some systems this can cause stability problems & where it does you should set Off.