I'll be interested to see what kind of responses you get Jim, but I noted on the B&H page that the 1000X offers "Min Read Speed: 150MB/s Write Speed: 145MB/s" and the 800X offers "Max. Read Speed: 120MB/s Max. Write Speed: 45MB/s". These specs are written VERY differently, and I am wholly suspicious of exactly what they mean! "Min" versus "Max" and one that doesn't say which it is... And all related to a "1000X" versus a "800X" (which would imply to me that one is ~20% faster than the other).