Good info. Have you been able to replicate it, does it happen every time?
Ok, this should be a pretty good drive. MLC nand, sandforce controller, and it has dram. I'll say right now, I doubt that drive is dieing(I asked a bunch of questions, cause they're related to what causes SSD slowdowns, and you didn't have any issues). When the anomaly shows itself, you mention the speed shows as 500kbps, but does it seem really slow? When the anomaly shows itself, are you able to get an idea how much system ram is available? Has the system been on for a long time with no resets? Has there been a lot of drive activity?