Plot of access times on a Panasonic Class 10 SDHC card

This is a plot of read access times, in page granularity, on the first 32MB of a Panasonic Class 10 SDHC card. This plot illustrates various properties of the card. The segment size of 4MB can clearly be seen from the various changes in performance at the boundaries between segments. All closed segments have the same read performance, as do have all erased segments, which are a little faster to read. The FAT area in the second segment is a bit slower when reading because it uses a block remapping algorithm. One segment has been opened for writing by writing a few blocks in the middle before the read test, that segment can be seen as being a little faster to read on this specific card. Also, an effect of multi-level-cell (MLC) flash is that it alternates between slightly slower and faster pages, which the plot shows as two parallel lines for some segments.